Patent Publication Number: US-2022231152-A1

Title: Tiled Lateral Thyristor

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. Non-Provisional application Ser. No. 16/894,259, filed Jun. 5, 2020, which is a continuation of U.S. Non-Provisional application Ser. No. 15/993,384, filed May 30, 2018, all of which is incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     There is an advantage to having a general design for an electronic component, such as a thyristor, or silicon-controlled rectifier (SCR), that allows for the same general design to be adapted for use in a wide variety of design applications. For example, spatial constraints within an overall integrated circuit layout can severely restrict a design choice for placement and layout of the thyristor device, thereby potentially adversely affecting desired performance characteristics thereof. 
     Additionally, it is generally very difficult to make a thyristor, or SCR, on a semiconductor-on-insulator (SOI) substrate or platform. However, given the prevalence of SOI technologies, it would be advantageous to be able to form a thyristor device on an SOI wafer or substrate. 
     SUMMARY 
     In accordance with some embodiments, a thyristor tile includes first and second PNP tiles and first and second NPN tiles. Each PNP tile is adjacent to both NPN tiles; and each NPN tile is adjacent to both PNP tiles. 
     In some embodiments, the first and second PNP tiles have a first orientation; and the first and second NPN tiles have a second orientation that is perpendicular to the first orientation. 
     In some embodiments, each of the first and second PNP tiles have an N-type base region and a P-type emitter region aligned in the first orientation; and each of the first and second NPN tiles have a P-type base region and an N-type emitter region aligned in the second orientation. 
     In some embodiments, each N-type base region is aligned in the first orientation with the N-type emitter region of one of the first and second NPN tiles and is an N-type collector region of that NPN tile; and each P-type base region is aligned in the second orientation with the P-type emitter region of one of the first and second PNP tiles and is a P-type collector region of that PNP tile. 
     In some embodiments, the first and second PNP tiles each have a second N-type base region aligned in the first orientation with the first N-type base region and the P-type emitter region; and the first and second NPN tiles each have a second P-type base region aligned in the second orientation with the first P-type base region and the N-type emitter region. 
     In some embodiments, the thyristor tile further includes a first interconnect layer that electrically connects the N-type base regions of the first and second PNP tiles; a second interconnect layer that electrically connects the P-type base regions of the first and second NPN tiles; a third interconnect layer that electrically connects the N-type emitter regions of the first and second NPN tiles; and a fourth interconnect layer that electrically connects the P-type emitter regions of the first and second PNP tiles. 
     In some embodiments, the thyristor tile is formed with a horizontal longitudinal dimension and a horizontal lateral dimension; the first interconnect layer includes 1) first island traces that electrically connect to the P-type emitter regions, 2) second island traces that electrically connect to the N-type emitter regions, 3) third island traces that electrically connect to the P-type base regions, and 4) first lateral, longitudinal and diagonal traces that electrically connect to the N-type base regions and that surround the first, second and third island traces; the second interconnect layer includes 1) fourth island traces that electrically connect to the P-type emitter regions, 2) fifth island traces that electrically connect to the N-type emitter regions, and 3) second lateral, longitudinal and diagonal traces that electrically connect to the P-type base regions and that surround the fourth and fifth island traces; and the third interconnect layer includes 1) sixth island traces that electrically connect to the P-type emitter regions, and 2) first and second sets of diagonal traces that electrically connect to the N-type emitter regions that are aligned along the same diagonals and that surround the sixth island traces. 
     In some embodiments, the first lateral, longitudinal and diagonal traces form first rectangular structures that surround the first island traces and form first octagonal structures that surround the second and third island traces; the second lateral, longitudinal and diagonal traces form second rectangular structures that surround the fifth island traces and form second octagonal structures that surround the fourth island traces; and the first and second sets of diagonal traces form rhombus structures that surround the sixth island traces. 
     In some embodiments, each NPN tile is formed within a P-well base; each PNP tile is formed within an N-well base; and the P-well bases are adjacent to the N-well bases, except at a corner between all four N-wells and P-wells. 
     In some embodiments, the first PNP tile is in a first quadrant of the thyristor tile; the first NPN tile is in a second quadrant of the thyristor tile, the second quadrant being located adjacent to the first quadrant; the second PNP tile is in a third quadrant of the thyristor tile, the third quadrant being located adjacent to the second quadrant, and the third quadrant being diagonally located from the first quadrant; and the second NPN tile is in a fourth quadrant of the thyristor tile, the fourth quadrant being located adjacent to the first and third quadrants, and the fourth quadrant being diagonally located from the second quadrant. 
     In some embodiments, an improved thyristor includes a plurality of the thyristor tile of claim  10 . The first NPN tile in the second quadrant of a first one of the plurality of the thyristor tile is located adjacent to the first PNP tile in the first quadrant of a second one of the plurality of the thyristor tile. A first N-type base region of the first PNP tile in the first quadrant of the second one of the plurality of the thyristor tile is a first N-type collector region of the first NPN tile in the second quadrant of the first one of the plurality of the thyristor tile. In some embodiments, the first NPN tile in the second quadrant of the first one of the plurality of the thyristor tile is located adjacent to the second PNP tile in the third quadrant of a third one of the plurality of the thyristor tile; and a first P-type base region of the first NPN tile in the second quadrant of the first one of the plurality of the thyristor tile is a first P-type collector region of the second PNP tile in the third quadrant of the third one of the plurality of the thyristor tile. 
     In accordance with some embodiments, an improved thyristor includes a plurality of PNP tiles and a plurality of NPN tiles. The PNP tiles and the NPN tiles are arranged in an alternating configuration in both rows and columns. 
     In some embodiments, each PNP tile is adjacent to at least two of the NPN tiles; and each NPN tile is adjacent to at least two of the PNP tiles. 
     In some embodiments, each PNP tile has at least one base region that is also a collector region of an adjacent NPN tile; and each NPN tile has at least one base region that is also a collector region of an adjacent PNP tile. 
     In some embodiments, the PNP tiles have a first orientation; and the NPN tiles have a second orientation that is perpendicular to the first orientation. 
     In some embodiments, each PNP tile has first and second N-type base regions and a P-type emitter region, the P-type emitter region being located between the first and second N-type base regions, and the first and second N-type base regions and the P-type emitter region being aligned in the first orientation; and each NPN tile has first and second P-type base regions and an N-type emitter region, the N-type emitter region being located between the first and second P-type base regions, and the first and second P-type base regions and the N-type emitter region being aligned in the second orientation. 
     In some embodiments, at least one of the first and second N-type base regions of each PNP tile is aligned in the first orientation with the N-type emitter region of an adjacent one of the NPN tiles; the at least one of the first and second N-type base regions of each PNP tile is also an N-type collector region of the adjacent one of the NPN tiles; at least one of the first and second P-type base regions of each NPN tile is aligned in the second orientation with the P-type emitter region of an adjacent one of the PNP tiles; and the at least one of the first and second P-type base regions of each NPN tile is also a P-type collector region of the adjacent one of the PNP tiles. 
     In some embodiments, the thyristor further includes a first interconnect layer that electrically connects the N-type base regions of the PNP tiles and the N-type collector regions of the NPN tiles, the first interconnect layer including first traces that surround the P-type emitter regions, the N-type emitter regions, and the P-type base regions in a first plane vertically offset therefrom; a second interconnect layer that electrically connects the P-type base regions of the NPN tiles and the P-type collector regions of the PNP tiles, the second interconnect layer including second traces that surround the P-type emitter regions and the N-type emitter regions in a second plane vertically offset therefrom; a third interconnect layer that electrically connects the N-type emitter regions of the NPN tiles, the third interconnect layer including third traces that surround the P-type emitter regions in a third plane vertically offset therefrom; and a fourth interconnect layer that electrically connects the P-type emitter regions of the PNP tiles. 
     In some embodiments, the first traces form first rectangular structures that surround the P-type emitter regions and form first octagonal structures that surround the N-type emitter regions and the P-type base regions; the second traces form second rectangular structures that surround the N-type emitter regions and form second octagonal structures that surround the P-type emitter regions; and the third traces include diagonal traces that form rhombus structures that surround the P-type emitter regions. 
     In some embodiments, the first, second, third and fourth interconnect layers are configured to receive an electrical connection thereto at any point along any peripheral side thereof for electrical interconnections to other electronic components of an overall electronic circuit of which the thyristor is a part. 
     In some embodiments, the PNP tiles and the NPN tiles are formed within a CMOS process flow simultaneously with portions of MOSFET devices of an overall electronic circuit of which the thyristor is a part. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a simplified schematic diagram of a thyristor or semiconductor-controlled rectifier (SCR). 
         FIG. 2  is a simplified top view layout of an example horizontal or lateral thyristor tile, in accordance with some embodiments. 
         FIGS. 3 and 4  are simplified cross section diagrams of the horizontal or lateral thyristor tile shown in  FIG. 2 , in accordance with some embodiments. 
         FIGS. 5-7  are simplified diagrams of example horizontal or lateral thyristor devices formed with a plurality of the horizontal or lateral thyristor tile shown in  FIGS. 2-4 , in accordance with some embodiments. 
         FIGS. 8-11  are simplified diagrams of example interconnect layers and vias for electrically connecting components of an example horizontal or lateral thyristor device formed with a plurality of the horizontal or lateral thyristor tile shown in  FIGS. 2-4 , in accordance with some embodiments. 
         FIGS. 12-15  are simplified current-voltage graphs showing the performance of an example horizontal or lateral thyristor device formed with a plurality of the horizontal or lateral thyristor tile shown in  FIGS. 2-4 , in accordance with some embodiments. 
         FIGS. 16-18  are simplified current-voltage graphs showing the results of transmission line pulse (TLP) tests, for example, horizontal or lateral thyristor devices formed with a plurality of the horizontal or lateral thyristor tile shown in  FIGS. 2-4 , in accordance with some embodiments. 
         FIG. 19  is a simplified schematic diagram of a thyristor with optional triggers. 
         FIGS. 20-26  are simplified current-voltage graphs showing the performance of an example horizontal or lateral thyristor device formed with a plurality of the horizontal or lateral thyristor tile shown in  FIGS. 2-4 , in accordance with some embodiments. 
         FIG. 27  is a simplified flowchart for an example method of fabricating the thyristor tile shown in  FIGS. 1-4 . 
     
    
    
     DETAILED DESCRIPTION 
     A simplified schematic diagram of a thyristor  100  is shown in  FIG. 1 ; and a simplified top view layout of an example horizontal or lateral thyristor tile  200  is shown in  FIG. 2 , in accordance with some embodiments. Disclosed herein is an improved design, geometry, structure, placement or layout for the thyristor  100  incorporating multiple instances of the horizontal or lateral thyristor tiles  200  formed from individual PNP tiles (or “PNP BJT sub-tiles”) and NPN tiles (or “NPN BJT sub-tiles”), as described below. The design of the thyristor tiles  200  allows for a high level of flexibility in design-stage control over device placement and layout, structural feature geometry, and operating parameters of the resulting horizontal or lateral thyristor  100  that can be easily incorporated within the spatial constraints of an overall integrated circuit layout with little or no adverse effects on the available circuit area, including embodiments advantageously formed on a semiconductor-on-insulator (SOI) wafer. Additionally, at least some portions of the thyristor  100  may be formed simultaneously with, i.e., during an overall complementary metal-oxide-semiconductor (CMOS) process flow, some regions of metal-oxide-semiconductor field-effect transistors (MOSFETs) incorporated in the overall electronic circuit within an integrated circuit of which the thyristor  100  is a part, thereby enhancing ease of incorporation of the thyristor  100  into the overall electronic circuit, particularly for integrated circuits formed in and on an SOI wafer. Furthermore, electrical interconnect (or metal) layers of the thyristor  100  allow for electrical connections to the thyristor at any or all sides thereof; thereby further enhancing the ease with which the thyristor  100  can be incorporated in the overall electronic circuit. In addition, the design or configuration of the thyristor  100  (including the thyristor tiles  200  and the electrical interconnect layers) allows for flexible triggering thereof. Additional advantages or improvements will be described below or will be apparent from the following description. 
     As shown in  FIG. 1 , the thyristor  100  generally includes a PNP BJT (bipolar junction transistor) device  101  and an NPN BJT device  102 . The PNP BJT device  101  includes a PNP P-type emitter  103 , and the NPN BJT device  101  includes an NPN N-type emitter  104 . Additionally, the PNP BJT device  101  includes a PNP N-type base  105  and the NPN BJT device  102  includes an NPN N-type collector  106  that are formed or connected together as an N-type base/collector (or a PNP-base/NPN-collector)  105 / 106 . Also, the NPN BJT device  102  includes an NPN P-type base  107  and the PNP BJT device  101  includes a PNP P-type collector  108  that are formed or connected together as a P-type base/collector (or an NPN-base/PNP-collector)  107 / 108 . 
     As shown in  FIG. 2 , the thyristor tile  200  generally includes first and second PNP tiles  201  and  202  and first and second NPN tiles  203  and  204 , which are not necessarily drawn to scale. Each PNP tile  201  and  202  is adjacent to both NPN tiles  203  and  204 , and each NPN tile  203  and  204  is adjacent to both PNP tiles  201  and  202 . However, the PNP tiles  201  and  202  are not adjacent to each other, and the NPN tiles  203  and  204  are not adjacent to each other. Instead, the PNP tiles  201  and  202  are offset diagonally from each other (e.g., top left to bottom right), and the NPN tiles  203  and  204  are offset diagonally from each other (e.g., top right to bottom left). It is understood, however, that the specific top/bottom and left/right locations for the tiles  201 - 204  are provided for illustrative and explanatory purposes only since the relative locations for the PNP tiles  201  and  202  can be switched with that of the NPN tiles  203  and  204 . 
     Additionally, the thyristor tile  200  may be part of an overall horizontal or lateral thyristor device, which further includes a plurality of thyristor tiles (not shown, but each similar to  200 ), such that PNP tiles (each similar to  201  or  202 ) and NPN tiles (each similar to  203  or  204 ) are arranged in an alternating configuration in both rows and columns, as described below with respect to  FIGS. 5-7 . Thus, each PNP or NPN type of tile is adjacent to at least two tiles of the opposite type (e.g., two tiles at a row/column corner, three tiles at a row or column edge, or four tiles within an interior of the rows and columns). 
     Each PNP tile  201  and  202  generally includes a P-type emitter region  201   a  and  202   a,  a first N-type base region  201   b  and  202   b,  a second N-type base region  201   c  and  202   c,  an N-well base region  201   d  and  202   d,  emitter contacts  201   e  and  202   e,  first base contacts  201   f  and  202   f,  and second base contacts  201   g  and  202   g.  Similarly, each NPN tile  203  and  204  generally includes an N-type emitter region  203   a  and  204   a,  a first P-type base region  203   b  and  204   b,  a second P-type base region  203   c  and  204   c,  a P-well base region  203   d  and  204   d,  emitter contacts  203   e  and  204   e,  first base contacts  203   f  and  204   f,  and second base contacts  203   g  and  204   g.  The emitter regions  201   a,    202   a,    203   a  and  204   a  are square shaped structures in the center of the N-well and P-well base regions  201   d,    202   d,    203   d  and  204   d,  respectively. The base regions  201   b/c,    202   b/c,    203   b/c  and  204   b/c  are rectangles adjacent to either the longitudinal or the lateral edges of the N-well and P-well base regions  201   d,    202   d,    203   d  and  204   d,  respectively. The emitter and base regions are, thus, symmetrical with respect to the center of the tiles  201 - 204 . The resulting structures are, thus, nearly identical, but rotated 90 degrees or oriented perpendicular to each other. Additional elements or details may not be shown for simplicity; whereas other elements may be shown, but not labeled to prevent overcrowding of the drawing. 
     For each PNP or NPN tile  201 - 204 , the corresponding collector region is provided by an adjacent P-type or N-type base region of an adjacent PNP or NPN tile  201 - 204 . For example, the first N-type base region  201   b  and  202   b  of each PNP tile  201  and  202  is also an N-type collector region for the adjacent NPN tile  203  and  204 , respectively. Similarly, the first P-type base region  203   b  and  204   b  of each NPN tile  203  and  204  is also a P-type collector region for the adjacent PNP tile  202  and  201 , respectively. Additionally, since the thyristor tile  200  may be part of an overall horizontal or lateral thyristor device, which further includes a plurality of thyristor tiles (not shown, but each similar to  200 ), the second N-type base region  201   c  and  202   c  of each PNP tile  201  and  202  may also be an N-type collector region for another adjacent NPN tile (similar to  203  and  204 ), unless the PNP tile  201  or  202  is at an edge or corner of the overall thyristor device, such that there is no additional NPN tile adjacent to the second N-type base region  201   c  or  202   c.  Similarly, the second P-type base region  203   c  and  204   c  of each NPN tile  203  and  204  may also be a P-type collector region for another adjacent PNP tile (similar to  201  and  202 ), unless the NPN tile  203  or  204  is at an edge or corner of the overall thyristor device, such that there is no additional PNP tile adjacent to the second P-type base region  203   c  or  204   c.  Therefore, the base regions  201   b/c,    202   b/c,    203   b/c  and  204   b/c  may also be referred to herein as collector regions  201   b/c,    202   b/c,    203   b/c  and  204   b/c  or base/collector regions  201   b/c,    202   b/c,    203   b/c  and  204   b/c  (for each base region  201   b/c,    202   b/c,    203   b/c  or  204   b/c  that is also a collector region). In a similar vein, the base contacts  201   f/g,    202   f/g,    203   f/g  and  204   f/g  (corresponding to the base regions  201   b/c,    202   b/c,    203   b/c  and  204   b/c,  respectively) may also be referred to herein as collector contacts  201   f/g,    202   f/g,    203   f/g  and  204   f/g  or base/collector contacts  201   f/g,    202   f/g,    203   f/g  and  204   f/g  (for each corresponding base region that is also a collector region) Additionally, although the tiles  201 - 204  are described as PNP and NPN BJT tiles, it is understood that the collector region for each type of BJT tile lies outside the BJT tile in an adjacent BJT tile of the opposite type. 
     The emitter regions  201   a,    202   a,    203   a  and  204   a  and the base/collector regions  201   b/c,    202   b/c,    203   b/c  and  204   b/c  are generally formed as structural islands in the corresponding N-well and P-well base regions  201   d,    202   d,    203   d  and  204   d.  The N-well and P-well base regions  201   d,    202   d,    203   d  and  204   d,  thus, serve as the base for a BJT formed by each emitter region  201   a,    202   a,    203   a  and  204   a  and corresponding collector region  204   b,    203   b,    201   b  and  202   b,  respectively, as indicated by PNP and NPN BJT schematics  201   h,    202   h,    203   h  and  204   h  overlaying the tiles  201 - 204 . Additionally, since the thyristor tile  200  may be part of an overall thyristor device, which further includes a plurality of thyristor tiles (not shown, but each similar to  200 ), the N-well and P-well base regions  201   d,    202   d,    203   d  and  204   d  may also serve as the base for a BJT formed by each emitter region  201   a,    202   a,    203   a  and  204   a  and another corresponding collector region of another adjacent NPN or PNP tile (similar to  201 - 204 ), except for the tiles  201 - 204  that are at an edge or corner of the overall thyristor device. Therefore, in comparison with the schematic diagram of the thyristor  100  ( FIG. 1 ), the P-type emitter regions  201   a  and  202   a  generally correspond to the PNP P-type emitter  103 , the N-type base/collector regions  201   b/c  and  202   b/c  generally correspond to the N-type base/collector  105 / 106 , the P-type base/collector regions  203   b/c  and  204   b/c  generally correspond to the P-type base/collector  107 / 108 , and the N-type emitter regions  203   a  and  204   a  generally correspond to the NPN N-type emitter  104 . 
     An optional opening or hole  205  is shown at the corners of all four tiles  201 - 204 , where all four tiles  201 - 204  would otherwise come together at a shared corner point, so that each tile  201 - 204  (or the N-well and P-well base regions  201   d,    202   d,    203   d  and  204   d ) has a generally octagonal shape. The hole  205  may be filled with intrinsic silicon, an N-type low doped silicon, or an insulating material. The hole  205 , thus, prevents the PNP tiles  201  and  202  from contacting each other, and prevents the NPN tiles  203  and  204  from contacting each other, so that these components are not shorted out, but are electrically isolated from each other. Additionally, since the thyristor tile  200  may be part of an overall horizontal or lateral thyristor device, which further includes a plurality of thyristor tiles (not shown, but each similar to  200 ), there is a similar hole at the shared corner point of every possible group of four tiles  201 - 204 , except for the tiles  201 - 204  that are at an edge or corner of the overall thyristor device, such that there is no additional NPN or PNP tile adjacent thereto. 
     In some embodiments, the thyristor tile  200  is characterized as having four quadrants, the top left being a first quadrant (having the first PNP tile  201 ), the top right being a second quadrant (having the first NPN tile  203 , and being adjacent to the first quadrant), the bottom right being a third quadrant (having the second PNP tile  202 , and being adjacent to the second quadrant and diagonally located from the first quadrant), and the bottom left being a fourth quadrant (having the second NPN tile  204 , and being adjacent to the first and third quadrants and diagonally located from the second quadrant). Consequently, since the thyristor tile  200  may be part of an overall horizontal or lateral thyristor device, which further includes a plurality of thyristor tiles (not shown, but each similar to  200 ), the first PNP tile  201  in the first quadrant of the thyristor tile  200  is located laterally adjacent to the first NPN tile in the second quadrant (or longitudinally adjacent to the second NPN tile in the fourth quadrant) of another thyristor tile, unless the first PNP tile  201  is at an edge or corner of the overall thyristor device. Additionally, the first NPN tile  203  in the second quadrant of the thyristor tile  200  is located laterally adjacent to the first PNP tile in the first quadrant (or longitudinally adjacent to the second PNP tile in the third quadrant) of another thyristor tile, unless the first NPN tile  203  is at an edge or corner of the overall thyristor device. Additionally, the second PNP tile  202  in the third quadrant of the thyristor tile  200  is located laterally adjacent to the second NPN tile in the fourth quadrant (or longitudinally adjacent to the first NPN tile in the second quadrant) of another thyristor tile, unless the second PNP tile  202  is at an edge or corner of the overall thyristor device. Additionally, the second NPN tile  204  in the fourth quadrant of the thyristor tile  200  is located laterally adjacent to the second PNP tile in the third quadrant (or longitudinally adjacent to the first PNP tile in the first quadrant) of another thyristor tile, unless the second NPN tile  204  is at an edge or corner of the overall thyristor device. It is understood, however, that the specific top/bottom and left/right locations for the quadrants and/or the specific relationships between the quadrants are provided for illustrative and explanatory purposes only, since the relative locations for the PNP tiles  201  and  202  can be switched with that of the NPN tiles  203  and  204 , and the quadrants can be rotated left or right and/or flipped longitudinally or laterally. 
     As mentioned above, the example horizontal or lateral thyristor tile  200  may be part of an overall horizontal or lateral thyristor device. In this sense, the terms “horizontal” and “lateral” refer to the plane of the thyristor tile  200  shown in  FIG. 2 . Therefore, in some embodiments, the thyristor tile  200  is generally characterized as being formed within a horizontal or lateral length or longitudinal dimension (in direction Y) and within a horizontal or lateral width or lateral dimension (in direction X) in the horizontal plane. Additionally, the emitter region  201   a  and the base regions  201   b/c  of the first PNP tile  201  are generally characterized as having (or being aligned in) a first orientation (e.g., in the lateral dimension, direction X); and the emitter region  202   a  and the base regions  202   b/c  of the second PNP tile  202  are also generally characterized as having (or being aligned in) the first orientation. Similarly, the emitter region  203   a  and the base regions  203   b/c  of the first NPN tile  203  are generally characterized as having (or being aligned in) a second orientation (e.g., in the longitudinal dimension, direction Y) that is perpendicular to the first orientation; and the emitter region  204   a  and the base regions  204   b/c  of the second NPN tile  204  are also generally characterized as having (or being aligned in) the second orientation. Furthermore, each N-type base region  201   b  or  202   b  of the PNP tile  201  or  202  is aligned in the first orientation with the N-type emitter region  203   a  or  204   a,  respectively, of the adjacent NPN tile  203  or  204  for which the N-type base region  201   b  or  202   b  is also the N-type collector region; and unless the PNP tile  201  or  202  is at an edge or corner of the overall thyristor device, each N-type base region  201   c  or  202   c  of the PNP tile  201  or  202  is aligned in the first orientation with the N-type emitter region (similar to  203   a  or  204   a ) of an adjacent NPN tile (similar to  203  or  204 ) for which the N-type base region  201   c  or  202   c  is also the N-type collector region. Similarly, each P-type base region  203   b  or  204   b  of the NPN tile  203  or  204  is aligned in the second orientation with the P-type emitter region  202   a  or  201   a,  respectively, of the adjacent PNP tile  202  or  201  for which the P-type base region  203   b  or  204   b  is also the P-type collector region; and unless the NPN tile  203  or  204  is at an edge or corner of the overall thyristor device, each P-type base region  203   c  or  204   c  of the NPN tile  203  or  204  is aligned in the second orientation with the P-type emitter region (similar to  202   a  or  201   a ) of an adjacent PNP tile (similar to  202  or  201 ) for which the P-type base region  203   c  or  204   c  is also the P-type collector region. 
     If a PNP or NPN tile (e.g.,  201 - 204 ) is at a row/column corner of the overall thyristor device, then that tile has only one collector region and only one of its base regions is used as a collector region for another tile. If a PNP or NPN tile (e.g.,  201 - 204 ) is at a row or column edge of the overall thyristor device, and if the alignment of the emitter and base regions of the PNP or NPN tile is oriented or aligned parallel with the edge, then that tile has only one collector region, but both of its base regions are used as collector regions for another tile. If a PNP or NPN tile (e.g.,  201 - 204 ) is at a row or column edge of the overall thyristor device, and if the alignment of the emitter and base regions of the PNP or NPN tile is oriented or aligned perpendicular to the edge, then that tile has two collector regions, but only one of its base regions is used as a collector region for another tile. 
       FIGS. 3 and 4  show simplified example cross sections of the thyristor tile  200  taken along section, or cut, lines  206  and  207 , respectively, in accordance with some embodiments.  FIGS. 3 and 4  further illustrate an example of the layout and structural feature geometry of the thyristor tile  200 , and are not necessarily drawn to scale.  FIGS. 3 and 4  illustrate that the thyristor tile  200  is generally formed within a vertical thickness (in direction Z), as well as within the aforementioned horizontal or lateral length or longitudinal dimension (in direction Y) and the horizontal or lateral width or lateral dimension (in direction X) in the horizontal plane. 
       FIG. 3  (cross section through cut line  206 ) shows an example cross section with the second PNP tile  202  on the right and the second NPN tile  204  on the left. (A similar cross section, not shown, would illustrate the first PNP tile  201  and the first NPN tile  203  in a similar manner using reference numbers with appropriate designations for the tiles  201  and  203 .)  FIG. 3  shows an active region containing the P-type emitter region  202   a,  the first and second N-type base/collector regions  202   b/c,  the N-well base region  202   d,  the emitter contacts  202   e,  and the first and second base/collector contacts  202   f/g  of the second PNP tile  202 , and the N-type emitter region  204   a,  the P-well base region  204   d,  and the emitter contacts  204   e  of the second NPN tile  204 . The active region also contains a P+ emitter connector region  202   i  and N+ base/collector (or “base” or “collector”) connector regions  202   j/k  of the second PNP tile  202 , and an N+ emitter connector region  204   i  of the second NPN tile  204 . Additionally, a buried oxide (BOX) layer  301  and an underlying substrate  302  are shown for embodiments formed in and on an SOI wafer. The BOX layer  301  is optional, since other embodiments may be formed in and on a bulk semiconductor wafer, i.e., without a buried oxide. Furthermore, a field oxide layer  303  is shown overlying the active region. The first N-type base/collector region  202   b,  the P-well base region  204   d,  and the N-type emitter region  204   a  form a collector, base and emitter, respectively, of an NPN BJT device, as indicated by an NPN BJT schematic  304  overlaying the cross section, but with the base connector outside the plane of this cross section. 
       FIG. 4  (cross section through cut line  207 ) shows an example cross section with the first PNP tile  201  on the right and the second NPN tile  204  on the left. (A similar cross section, not shown, would illustrate the second PNP tile  202  and the first NPN tile  203  in a similar manner using reference numbers with appropriate designations for the tiles  202  and  203 .)  FIG. 4  shows the active region containing the P-type emitter region  201   a,  the N-well base region  201   d,  and the emitter contacts  201   e  of the first PNP tile  201 , and the N-type emitter region  204   a,  the first and second P-type base/collector regions  204   b/c,  the P-well base region  204   d,  the emitter contacts  204   e,  the first and second base/collector contacts  204   f/g,  and the N+ emitter connector region  204   i  of the second NPN tile  204 . The active region also contains a P+ emitter connector region  201   i  of the first PNP tile  201 , and a P+ base/collector (or “base” or “collector”) connector regions  204   j/k  of the second NPN tile  204 . Additionally, the buried oxide (BOX) layer  301  and the underlying substrate  302  are shown for embodiments formed in and on an SOI wafer. Furthermore, the field oxide layer  303  is shown overlying the active region. The first P-type base/collector region  204   b,  the N-well base region  201   d,  and the P-type emitter region  201   a  form a collector, base and emitter, respectively, of a PNP BJT device, as indicated by a PNP BJT schematic  401  overlaying the cross section, but with the base connector outside the plane of this cross section. 
     To form the structures shown in  FIGS. 3 and 4 , the N-well base regions  201   d  and  202   d  and the P-well base region  204   d  are epitaxially grown on the buried oxide layer  301  or implanted (e.g., with appropriate N or P type dopants, respectively) into an appropriate semiconductor layer (e.g., an intrinsic silicon layer, an N-minus layer, or a P-minus layer) overlying the buried oxide layer  301 . The first and second N-type base/collector regions  202   b/c  and the N-type emitter region  204   a  are implanted (e.g., with an appropriate N type dopant) into the N-well base region  202   d  and the P-well base region  204   d,  respectively. The first and second N-type base/collector regions  202   b/c  and the N-type emitter region  204   a  may generally have a higher net active implant concentration than that of the N-well base regions  201   d  and  202   d.  The P-type emitter regions  201   a  and  202   a  and the P-type base/collector regions  204   b/c  are implanted (e.g., with an appropriate P type dopant) into the N-well base regions  201   d  and  202   d  and the P-well base region  204   d,  respectively. The P-type emitter regions  201   a  and  202   a  and the P-type base/collector regions  204   b/c  may generally have a higher net active implant concentration than that of the P-well base region  204   d.  The N+ base/collector connector regions  202   j/k  and the N+ emitter connector region  204   i  (along with other N+ connector regions not shown or labeled in the drawings) are implanted (e.g., with an appropriate N type dopant) into the first and second N-type base/collector regions  202   b/c  and the N-type emitter region  204   a,  respectively. The N+ base/collector connector regions  202   j/k  and the N+ emitter connector region  204   i  may generally have a higher net active implant concentration than that of the first and second N-type base/collector regions  202   b/c  and the N-type emitter region  204   a.  This higher net active implant concentration provides a highly doped ohmic contact between the first and second N-type base/collector regions  202   b/c  and the first and second base/collector contacts  202   f/g,  respectively, and between the N-type emitter region  204   a  and the emitter contacts  204   e.  The P+ emitter connector regions  201   i  and  202   i  and the P+ base/collector connector regions  204   j/k  (along with other P+ connector regions not shown or labeled in the drawings) are implanted (e.g., with an appropriate P type dopant) into the P-type emitter regions  201   a  and  202   a  and the P-type base/collector regions  204   b/c,  respectively. The P+ emitter connector regions  201   i  and  202   i  and the P+ base/collector connector regions  204   j/k  may generally have a higher net active implant concentration than that of the P-type emitter regions  201   a  and  202   a  and the P-type base/collector regions  204   b/c.  This higher net active implant concentration provides a highly doped ohmic contact between the P-type emitter regions  201   a  and  202   a  and the emitter contacts  201   e  and  202   e,  respectively, and between the first and second P-type base/collector regions  204   b/c  and the first and second base/collector contacts  204   f/g,  respectively. The field oxide layer  303  is deposited over a top surface of the active region. The emitter contacts  201   e,    202   e  and  204   e  and the base/collector contacts  202   f/g  and  204   f/g  are formed through the field oxide layer  303  to electrically contact the P+ emitter connector region  201   i,    202   i,  the N+ emitter connector region  204   i,  the N+ base/collector connector regions  202   j/k,  and the P+ base/collector connector regions  204   j/k,  respectively. Additional electrical interconnect (e.g., metal) layers alternating with insulator layers (e.g., with electrical vias therethrough) are deposited over the contacts  201   e,    202   e/f/g  and  204   e/f/g  and the field oxide layer  303 , as described below with respect to  FIGS. 8-11 . 
       FIGS. 2-4  illustrate how the PNP and NPN tiles (or subtiles)  201 - 204  form the thyristor tile  200  of an overall thyristor device, or a portion thereof. The placement of the emitter regions, base regions and collector regions show how the thyristor device is a horizontal or lateral current flow device.  FIGS. 5-7 , on the other hand, illustrate how a plurality of the thyristor tile  200  (i.e., a plurality of the PNP tiles  201  and  202  and a plurality of the NPN tiles  203  and  204 ) can be used to form overall horizontal or lateral thyristor devices, e.g., the thyristor  100  ( FIG. 1 ), in a manner that allows the structure of the thyristor to be scaled in accordance with the available area within the integrated circuit and to provide ESD (electrostatic discharge) protection for the integrated circuit. The high level of flexibility in the design-stage control of device placement, layout, and structural feature geometry allows for little or no need to change the integrated circuit layout to accommodate the resulting thyristor device. 
     The above-described structural feature geometry of the thyristor tile  200  enables a high level of flexibility in design-stage control over device layout for the resulting thyristor device, as illustrated by lateral thyristor devices  500 ,  600  and  700  in  FIGS. 5, 6 and 7 , respectively. The lateral thyristor devices  500 ,  600  and  700  are formed with a plurality of the lateral thyristor tile  200  arranged in a variety of overlapping configurations. The example configurations for the thyristor devices  500 ,  600  and  700  are shown for illustrative and explanatory purposes only. Other examples may have a variety of other appropriate configurations with other numbers of thyristor tiles that connect or overlap in the manner described herein. 
     The thyristor device  500  ( FIG. 5 ) includes four thyristor tiles  501 - 504 . Each thyristor tile  501 - 504  is similar to the thyristor tile  200 , so each thyristor tile  501 - 504  includes two PNP tiles ( 501   a/b,    502   a/b,    503   a/b  and  504   a/b ) and two NPN tiles ( 501   c/d,    502   c/d,    503   c/d  and  504   c/d ). Therefore, the thyristor tiles  501 - 504  are arranged in a 2×2 array or grid of rows and columns, and the PNP and NPN tiles ( 501   a - d,    502   a - d,    503   a - d  and  504   a - d ) are arranged in an alternating configuration in a 4×4 array or grid of both rows and columns. In other embodiments, additional thyristor tiles  200  could be added to this configuration to make a larger, wider or longer overall thyristor device. Adjacent PNP and NPN tiles ( 501   a - d,    502   a - d,    503   a - d  and  504   a - d ) share base/collector regions, base/collector connector regions, and base/collector contacts as described above. 
     The thyristor device  600  ( FIG. 6 ) includes four thyristor tiles  601 - 604 . Each thyristor tile  601 - 604  is similar to the thyristor tile  200 , so each thyristor tile  601 - 604  includes two PNP tiles ( 601   a/b,    602   a/b,    603   a/b  and  604   a/b ) and two NPN tiles ( 601   c/d,    602   c/d,    603   c/d  and  604   c/d ). Therefore, the thyristor tiles  601 - 604  are arranged in a 1×4 array or grid of rows and columns, and the PNP and NPN tiles ( 601   a - d,    602   a - d,    603   a - d  and  604   a - d ) are arranged in an alternating configuration in a 2×8 array or grid of both rows and columns. In other embodiments, additional thyristor tiles  200  could be added to this configuration to make a larger, wider or longer overall thyristor device. Adjacent PNP and NPN tiles ( 601   a - d,    602   a - d,    603   a - d  and  604   a - d ) share base/collector regions, base/collector connector regions, and base/collector contacts as described above. 
     The thyristor device  700  ( FIG. 7 ) includes four thyristor tiles  701 - 704 . Each thyristor tile  701 - 704  is similar to the thyristor tile  200 , so each thyristor tile  701 - 704  includes two PNP tiles ( 701   a/b,    702   a/b,    703   a/b  and  704   a/b ) and two NPN tiles ( 701   c/d,    702   c/d,    703   c/d  and  704   c/d ). Therefore, the thyristor tiles  701 - 704  are arranged in a 2×3 array or grid of rows and columns, and the PNP and NPN tiles ( 701   a - d,    702   a - d,    703   a - d  and  704   a - d ) are arranged in an alternating configuration in a 4×6 array or grid of both rows and columns; however, some of the row/column locations are empty, whereas other row/column locations are occupied. In other embodiments, additional thyristor tiles  200  could be added to this configuration to make a larger, wider or longer overall thyristor device. Adjacent PNP and NPN tiles ( 701   a - d,    702   a - d,    703   a - d  and  704   a - d ) share base/collector regions, base/collector connector regions, and base/collector contacts as described above. 
     Variations on the configurations shown in  FIGS. 5-7  can be implemented to form the thyristor  100  ( FIG. 1 ) by using almost any available space between other electronic components of an overall electronic circuit of which the thyristor  100  is a part. The use of a plurality of the thyristor tiles  200  thereby enhances the ease of incorporation of the thyristor  100  into the overall electronic circuit. On the other hand, conventional circuit layout techniques for thyristor devices generally require that thyristor tiles or cells be arranged in a rectangular structure to form the thyristor device. In order to fit the rectangular structure into an overall circuit layout, therefore, the footprint of the overall circuit layout might have to be increased to provide sufficient space for the rectangular structure, thereby potentially resulting in having to make revisions to the overall circuit layout. Thus, the ability of the thyristor tiles  200  to be arranged in a variety of multiple complex shapes, as illustrated by the examples in  FIGS. 5-7 , allows for optimum usage of available space within an existing overall circuit layout, thereby minimizing any potential need to revise the overall circuit layout to fit the resulting thyristor device into the overall circuit layout. The time for and cost of designing the thyristor device and the overall circuit are thus reduced. 
       FIGS. 8-11  show simplified diagrams of novel example interconnect layers (e.g., electrical interconnect or metal layers  800 ,  900 ,  1000  and  1100 ) and the underlying contacts or vias for electrically connecting components of an example horizontal or lateral thyristor device formed with a plurality of the thyristor tile  200  shown in  FIGS. 2-4 , in accordance with some embodiments. Each interconnect layer  800 ,  900 ,  1000  and  1100  corresponds to and forms a terminal of the thyristor device, e.g., the interconnect layer  800  corresponds to the N-type base/collector  105 / 106 , the interconnect layer  900  corresponds to the P-type base/collector  107 / 108 , the interconnect layer  1000  corresponds to the NPN N-type emitter  104 , and the interconnect layer  1100  corresponds to the PNP P-type emitter  103 , of the thyristor  100  shown in  FIG. 1 . Each interconnect layer  800 ,  900 ,  1000  and  1100 , thus, connects to the corresponding components of each underlying thyristor tile  200  in parallel. 
     The example layouts of the interconnect layers  800 ,  900 ,  1000  and  1100  are provided for an overall thyristor device similar to the lateral thyristor device  500  ( FIG. 5 ), i.e., with the thyristor tiles  501 - 504  arranged in a 2×2 array or grid of rows and columns, and the PNP and NPN tiles ( 501   a - d,    502   a - d,    503   a - d  and  504   a - d ) arranged in an alternating configuration in a 4×4 array or grid of both rows and columns. Similarly designed interconnect layer layouts can be provided for any other appropriate configuration for any other overall thyristor device, e.g., including the lateral thyristor devices  600  and  700  of  FIGS. 6 and 7 , among others. 
     The proper timing and distribution of electrical signals or currents provided to the emitter, base and collector connectors of the PNP and NPN tiles (e.g.,  201 - 204  or  501   a - 504   d ) is essential for the PNP and NPN tiles to operate in accord with each other, thereby ensuring proper functioning of the overall thyristor device (e.g.,  500 ,  600  and  700 ). The complex and novel example layouts or geometry of the interconnect layers  800 ,  900 ,  1000  and  1100 , therefore, ensure uniformity in the connections to the contacts  201   e/f/g,    202   e/f/g,    203   e/f/g  and  204   e/f/g  of the underlying thyristor tiles  200 , so that the electrical signals or currents are properly and evenly distributed thereto, thereby enabling the usage of the unique structure of the thyristor tiles  200  and the manufacturability and scalability of the lateral thyristor devices (e.g.,  500 ,  600  and  700 ). The interconnect layers  800 ,  900 ,  1000  and  1100  generally connect the contacts or terminals in a manner that ensures that current distribution through the various contacts, vias and interconnects is approximately equal and avoids current crowding throughout the structure of the lateral thyristor devices (e.g.,  500 ,  600  and  700 ). 
     The example interconnect layer  800  ( FIG. 8 ) generally includes a conductor trace  801  and a plurality of island traces  802 ,  803  and  804 . The conductor trace  801  and the island traces  802 - 804  may be any appropriate conductive material, such as copper, aluminum, another metal, or a non-metal electrical conductor, depending on the operational or design requirements or needs of the overall thyristor device or the overall electronic circuit and/or the availability or cost of materials. The example interconnect layer  800  is formed or deposited on top of the contacts  201   e/f/g,    202   e/f/g,    203   e/f/g  and  204   e/f/g  and the field oxide layer  303  and with insulation material between each of the traces  801 - 804 . 
     The conductor trace  801  electrically connects to the base/collector contacts (e.g.,  201   f/g  and  202   f/g ) and, thus, to the N-type base regions (e.g.,  201   b/c  and  202   b/c ) of the PNP tiles (e.g.,  201  and  202 ) of the thyristor tiles (e.g.,  200 ) of the overall thyristor device  500 . The island traces  802  electrically connect to the base/collector contacts (e.g.,  203   f/g  and  204   f/g ) of the NPN tiles (e.g.,  203  and  204 ). The island traces  803  electrically connect to the emitter contacts (e.g.,  203   e  and  204   e ) of the NPN tiles (e.g.,  203  and  204 ). The island traces  804  electrically connect to the emitter contacts (e.g.,  201   e  and  202   e ) of the PNP tiles (e.g.,  201  and  202 ). The contacts  201   e/f/g,    202   e/f/g,    203   e/f/g  and  204   e/f/g  are shown in dashed lines to signify that they are disposed under the example interconnect layer  800 . Further electrical interconnections from the conductor trace  801  to other electronic components of the overall electronic circuit or to external connection pads thereof are made from extensions at the periphery (e.g. a peripheral trace  811 ) of the conductor trace  801  through other conductor traces, vias and interconnect layers. 
     The structure of the conductor trace  801  generally includes traces, or trace portions, such as lateral traces  805 , longitudinal traces  806 , and diagonal traces  807 . The longitudinal traces  806  provide the electrical contacts or connections between the conductor trace  801  and the base/collector contacts (e.g.,  201   f/g  and  202   f/g ) and, thus, to the N-type base regions (e.g.,  201   b/c  and  202   b/c ). The lateral traces  805  and the longitudinal traces  806  connect at their endpoints to form generally rectangular structures that surround the island traces  804 . The lateral traces  805 , the longitudinal traces  806 , and the diagonal traces  807  connect at their endpoints to form generally octagonal structures that surround the island traces  802  and  803 . Thus, the diagonal traces  807  connect at their endpoints to vertices of the generally rectangular structures formed by the lateral traces  805  and the longitudinal traces  806 . The horizontal thicknesses of the lateral traces  805 , the longitudinal traces  806 , the diagonal traces  807 , and the island traces  802 - 804  are generally selected or designed to allow for appropriate clear distances between the traces  805 - 807  of the conductor trace  801  and the island traces  802 - 804 , depending on acceptable interconnect or metallization design rules and the operational or design requirements or needs of the overall thyristor device or the overall electronic circuit. 
     The example interconnect layer  900  ( FIG. 9 ) generally includes a conductor trace  902  and a plurality of island traces  903  and  904 . The conductor trace  902  and the island traces  903  and  904  may be any appropriate conductive material, such as copper, aluminum, another metal, or a non-metal electrical conductor, depending on the operational or design requirements or needs of the overall thyristor device or the overall electronic circuit and/or the availability or cost of materials. The example interconnect layer  900  is formed or deposited on top of an insulator layer (deposited on top of the interconnect layer  800 ) with electrical vias (described below) therethrough and with insulation material between each of the traces  902 - 904 . 
     The conductor trace  902  electrically connects to base/collector vias  905  that electrically connect to the island traces  802  ( FIG. 8 ) and to the base/collector contacts (e.g.,  203   f/g  and  204   f/g ) of the NPN tiles (e.g.,  203  and  204 ) of the thyristor tiles (e.g.,  200 ) of the overall thyristor device  500 . The island traces  903  electrically connect to emitter vias  906  that electrically connect to the island traces  803  ( FIG. 8 ) and to the emitter contacts (e.g.,  203   e  and  204   e ) of the NPN tiles (e.g.,  203  and  204 ). The island traces  904  electrically connect to emitter vias  907  that electrically connect to the island traces  804  ( FIG. 8 ) and to the emitter contacts (e.g.,  201   e  and  202   e ) of the PNP tiles (e.g.,  201  and  202 ). The vias  905 ,  906  and  907  are shown in dashed lines to signify that they are disposed under the example interconnect layer  900 , e.g., within and through the underlying insulator layer. Further electrical interconnections from the conductor trace  902  to other electronic components of the overall electronic circuit or to external connection pads thereof are made from extensions at the periphery (e.g. a peripheral trace  911 ) of the conductor trace  902  through other conductor traces, vias and interconnect layers. 
     The structure of the conductor trace  902  generally includes traces, or trace portions, such as lateral traces  908 , longitudinal traces  909 , and diagonal traces  910 . The lateral traces  908  provide the electrical contacts or connections between the conductor trace  902  and the base/collector vias  905  and, thus, to the island traces  802 , the base/collector contacts (e.g.,  203   f/g  and  204   f/g ), and the P-type base regions (e.g.,  203   b/c  and  204   b/c ). The lateral traces  908  and the longitudinal traces  909  connect at their endpoints to form generally rectangular structures that surround the island traces  903 . The lateral traces  908 , the longitudinal traces  909 , and the diagonal traces  910  connect at their endpoints to form generally octagonal structures that surround the island traces  904 . Thus, the diagonal traces  910  connect at their endpoints to vertices of the generally rectangular structures formed by the lateral traces  908  and the longitudinal traces  909 . The conductor trace  902 , therefore, has a generally similar configuration or geometry as that of the conductor trace  801  ( FIG. 8 ), but the rectangular and octagonal structures of the conductor trace  902  are shifted or offset relative to the similar structures of the conductor trace  801 , such that the octagonal structures of the conductor trace  902  are vertically aligned with the rectangular structures of the conductor trace  801 , and the rectangular structures of the conductor trace  902  are vertically aligned with the octagonal structures of the conductor trace  801 . The horizontal thicknesses of the lateral traces  908 , the longitudinal traces  909 , the diagonal traces  910 , and the island traces  903  and  904  are generally selected or designed to allow for appropriate clear distances between the traces  908 - 910  of the conductor trace  902  and the island traces  903  and  904 , depending on acceptable interconnect or metallization design rules and the operational or design requirements or needs of the overall thyristor device or the overall electronic circuit. For example, in this embodiment, a set of only two vias are shown for each group of the emitter vias  906  and  907  (as opposed to the set of four contacts, as was shown for each group of the contacts  201   e,    202   e,    203   e  and  204   e  in  FIG. 8 ), and the island traces  903  and  904  are shown as small rectangles (smaller than the squares shown for the island traces  803  and  804 ), in order to pass acceptable interconnect or metallization design rule checks, and so that the overall thyristor device has optimum performance characteristics. 
     Although the first example interconnect layer  800  and the second example interconnect layer  900  are shown and described for electrically connecting (directly or indirectly) to the PNP base/collector contacts  201   f/g  and  202   f/g  and the NPN base/collector contacts  203   f/g  and  204   f/g,  respectively, it is understood that these electrical connections may be reversed. In other words, in other embodiments, the NPN base/collector contacts  203   f/g  and  204   f/g  could be electrically connected through the first interconnect layer, and the PNP base/collector contacts  201   f/g  and  202   f/g  could be electrically connected through the second interconnect layer. 
     The example interconnect layer  1000  ( FIG. 10 ) generally includes a conductor trace  1003  and a plurality of island traces  1004 . The conductor trace  1003  and the island traces  1004  may be any appropriate conductive material, such as copper, aluminum, another metal, or a non-metal electrical conductor, depending on the operational or design requirements or needs of the overall thyristor device or the overall electronic circuit and/or the availability or cost of materials. The example interconnect layer  1000  is formed or deposited on top of an insulator layer (deposited on top of the interconnect layer  900 ) with electrical vias (described below) therethrough and with insulation material between each of the traces  1003  and  1004 . 
     The conductor trace  1003  electrically connects to emitter vias  1006  that electrically connect to the island traces  903  ( FIG. 9 ) and through to the emitter vias  906 , the island traces  803  ( FIG. 8 ), and the emitter contacts (e.g.,  203   e  and  204   e ) of the NPN tiles (e.g.,  203  and  204 ) of the thyristor tiles (e.g.,  200 ) of the overall thyristor device  500 . The island traces  1004  electrically connect to emitter vias  1007  that electrically connect to the island traces  904  and through to the emitter vias  907 , the island traces  804  ( FIG. 8 ), and the emitter contacts (e.g.,  201   e  and  202   e ) of the PNP tiles (e.g.,  201  and  202 ). The vias  1006  and  1007  are shown in dashed lines to signify that they are disposed under the example interconnect layer  1000 , e.g., within and through the underlying insulator layer. Further electrical interconnections from the conductor trace  1003  to other electronic components of the overall electronic circuit or to external connection pads thereof are made from extensions at the periphery (e.g. lateral peripheral traces  1008  and longitudinal peripheral traces  1009 ) of the conductor trace  1003  through other conductor traces, vias and interconnect layers. 
     The structure of the conductor trace  1003  generally includes traces, or trace portions, such as first and second sets of diagonal traces  1010  and  1011 . Each diagonal trace  1010  extends along or parallel to a first diagonal direction (e.g., at about a negative 45-degree angle relative to lateral peripheral traces  1008  and longitudinal peripheral traces  1009  or between top left and bottom right). Each diagonal trace  1011  extends along or parallel to a second diagonal direction (e.g., at about a positive 45-degree angle relative to the lateral peripheral traces  1008  and the longitudinal peripheral traces  1009  or between top right and bottom left). In some embodiments, the diagonal traces  1010  and  1011  are perpendicular to each other. The diagonal traces  1010  and  1011  generally form rhombus shapes, diamond shapes, or 45-degree-rotated rectangle or square shapes that surround the island traces  1004 . Each diagonal trace  1010  and  1011  electrically connects (e.g., through the emitter vias  1006 , the island traces  903 , the emitter vias  906 , the island traces  803 , and the emitter contacts  203   e  and  204   e ) to the N-type emitter regions (e.g.,  203   a  and  204   a ) of the NPN tiles (e.g.,  203  and  204 ) that are aligned along the same diagonal directions. The horizontal thicknesses of the diagonal traces  1010  and  1011  and the island traces  1004  are generally selected or designed to allow for appropriate clear distances between the diagonal traces  1010  and  1011  of the conductor trace  1003  and the island traces  1004 , depending on acceptable interconnect or metallization design rules and the operational or design requirements or needs of the overall thyristor device or the overall electronic circuit. 
     The example interconnect layer  1100  ( FIG. 11 ) generally includes a conductor trace  1104 . The conductor trace  1104  may be any appropriate conductive material, such as copper, aluminum, another metal, or a non-metal electrical conductor, depending on the operational or design requirements or needs of the overall thyristor device or the overall electronic circuit and/or the availability or cost of materials. The example interconnect layer  1100  is formed or deposited on top of an insulator layer (deposited on top of the interconnect layer  1000 ) with electrical vias (described below) therethrough. 
     The conductor trace  1104  electrically connects to emitter vias  1107  that electrically connect to the island traces  1004  ( FIG. 10 ) and through to the emitter vias  1007 , the island traces  904  ( FIG. 9 ), the emitter vias  907 , the island traces  804  ( FIG. 8 ), and the emitter contacts (e.g.,  201   e  and  202   e ) of the PNP tiles (e.g.,  201  and  202 ) of the thyristor tiles (e.g.,  200 ) of the overall thyristor device  500 . The emitter vias  1107  are shown in dashed lines to signify that they are disposed under the example interconnect layer  1100 , e.g., within and through the underlying insulator layer. Further electrical interconnections from the conductor trace  1104  to other electronic components of the overall electronic circuit or to external connection pads thereof are made from extensions at the periphery of the conductor trace  1104  through other conductor traces, vias and interconnect layers. 
     The structure of the conductor trace  1104  is generally that of a flat plate or sheet with periodically spaced holes or slots  1108 . The holes  1108  are generally rectangular or square shaped. The holes  1108  prevent or mitigate warpage or deformation of the conductor trace  1104  (and potential damage to adjacent underlying or overlying material layers) when the conductor trace  1104  becomes hot during operation of the thyristor device and the overall electronic circuit. Acceptable interconnect or metallization design rules typically require such holes to be spaced from via connections. Dotted-line squares  1109  are shown to represent such a required spacing distance around the emitter vias  1107 , so that the emitter vias  1107  are overlaid by a sufficient amount of the material of the interconnect layer  1100 . The holes  1108 , therefore, are shown outside the dotted-line squares  1109 . As a result, the holes  1108  are horizontally offset from the center of the underlying thyristor tiles (e.g.,  200 ). Alternatively, in some embodiments, the conductor trace  1104  of the fourth interconnect layer  1100  could have a generally similar configuration or geometry as that of the conductor trace  1003  ( FIG. 10 ) of the third interconnect layer  1000 , but with the diagonal traces  1010  and  1011  shifted or offset relative to the similar structures of the conductor trace  1003 , such that the intersections of the diagonal traces  1010  and  1011  are vertically aligned with the emitter vias  1107 . 
     Although the third example interconnect layer  1000  and the fourth example interconnect layer  1100  are shown and described for electrically connecting through to the NPN emitter contacts  203   e  and  204   e  and the PNP emitter contacts  201   e  and  202   e,  respectively, it is understood that these electrical connections may be reversed. In other words, in other embodiments, the PNP emitter contacts  201   e  and  202   e  could be electrically connected through the third interconnect layer, and the NPN emitter contacts  203   e  and  204   e  could be electrically connected through the fourth interconnect layer. 
     Additionally, each of the electrical interconnect or metal layers  800 ,  900 ,  1000  and  1100  has an outer edge or peripheral trace (e.g.,  811 ,  911 ,  1008 / 1009 ) that fully encompasses the entire electrical interconnect or metal layers  800 ,  900 ,  1000  and  1100 . In other words, each of the electrical interconnect or metal layers  800 ,  900 ,  1000  and  1100  is exposed on all four sides. In other words, the electrical interconnect or metal layers  800 ,  900 ,  1000  and  1100  are each configured to receive an electrical connection thereto at any point along any peripheral side thereof. Consequently, the electrical interconnections (from the electrical interconnect or metal layers  800 ,  900 ,  1000  and  1100  to other electronic components of the overall electronic circuit or to external connection pads thereof) can be made on any one or more (or all four) sides of the electrical interconnect or metal layers  800 ,  900 ,  1000  and  1100 . This feature enables the advantage of allowing easy electrical connection to the thyristor device  100  and placement of the thyristor device  100  at almost any available location within the overall electronic circuit or integrated circuit. In contrast, many prior art thyristor designs require electrical connections to be on a particular side of the thyristor; thereby restricting the potential for placing the thyristor within an overall integrated circuit. 
       FIGS. 12-18 and 20-26  show simplified graphs indicating the performance of example improved horizontal or lateral thyristor devices formed with a plurality of horizontal or lateral thyristor tiles (e.g., similar to the thyristor tile  200  shown in  FIGS. 2-4 ), in accordance with some embodiments. The data available in these graphs illustrate that the example improved horizontal or lateral thyristor devices perform or function as well as, or better than, a conventional thyristor device. 
       FIGS. 12 and 13  show simplified graphs  1200  and  1300  of reverse diode breakdown current (ID) versus voltage (VD) curves (I-V curves), and  FIGS. 14 and 15  show simplified graphs  1400  and  1500  of SCR breakdown I-V curves, for an example thyristor device. The example thyristor device in these tests incorporates a 4×4 array or grid of thyristor tiles (e.g., each similar to the thyristor tile  200 ). In the reverse diode configuration for the graphs  1200  and  1300 , a bias voltage is applied to the N-type base/collector (e.g.,  105  and  106  of  FIG. 1, and 201   b/c  and  202   b/c  of  FIG. 2 ), a ground is applied to the P-type base/collector (e.g.,  107  and  108  of  FIG. 1, and 203   b/c  and  204   b/c  of  FIG. 2 ), and the PNP and NPN emitters (e.g.,  103  and  104  of  FIG. 1, and 201   a,    202   a,    203   a  and  204   a  of  FIG. 2 ) are floating. In the SCR configuration for the graphs  1400  and  1500 , a bias voltage is applied to the PNP emitter (e.g.,  103  of  FIG. 1, and 201   a  and  202   a  of  FIG. 2 ) and the N-type base/collector (e.g.,  105  and  106  of  FIG. 1, and 201   b/c  and  202   b/c  of  FIG. 2 ), and a ground is applied to the NPN emitter (e.g.,  104  of  FIG. 1, and 203   a  and  204   a  of  FIG. 2 ) and the P-type base/collector (e.g.,  107  and  108  of  FIG. 1, and 203   b/c  and  204   b/c  of  FIG. 2 ). 
     The I-V curves  1300  and  1500  are provided with a linear scale for both the current and voltage, which, therefore, also allows for presentation of negative current and voltage values. The I-V curves  1200  and  1400  are provided with a logarithmic scale for the current (ID) and a linear scale for the voltage (VD), thereby showing enhanced details in the low voltage range. These tests were performed with direct current (DC) I-V sweeps from less than −1.0 volts to greater than 22 volts. All of the graphs show that the example thyristor device provided excellent voltage blocking capabilities up to about 22 volts. Additionally, the I-V curves  1200  and  1400  indicate that the thyristor device exhibited slightly more leakage current in the SCR configuration than in the reverse diode configuration. 
       FIGS. 16-18  show simplified current-voltage (I-V) and leakage current graphs  1601 ,  1602 ,  1701 ,  1702 ,  1801  and  1802  for the results of transmission line pulse (TLP) tests for three example horizontal or lateral thyristor devices (e.g., tiled SCR devices) formed with a plurality of horizontal or lateral thyristor tile (e.g., each similar to the thyristor tile  200  shown in  FIGS. 2-4 ), in accordance with some embodiments. The first example thyristor, or tiled SCR, device used for the tests for graphs  1601  and  1602  included a 4×4 array or grid of the thyristor tiles (e.g., each similar to the thyristor tile  200 ) and had horizontal length/width dimensions, or footprint, of about 33 μm by 33 μm. The second example thyristor, or tiled SCR, device used for the tests for graphs  1701  and  1702  included a 5×5 array or grid of the thyristor tiles (e.g., each similar to the thyristor tile  200 ) and had horizontal length/width dimensions of about 41 μm by 41 μm. The third example thyristor, or tiled SCR, device used for the tests for graphs  1801  and  1802  included a 6×6 array or grid of the thyristor tiles (e.g., each similar to the thyristor tile  200 ) and had horizontal length/width dimensions of about 49 μm by 49 μm. 
     To generate each of the graphs  1601 ,  1602 ,  1701 ,  1702 ,  1801  and  1802 , a trigger voltage of about one volt was used, as indicated by a vertical dashed line  1803 . The graphs  1602 ,  1702  and  1802  show the current-voltage characteristics (bottom horizontal axis) of the three example thyristors. The graphs  1601 ,  1701  and  1801  show the leakage current (top horizontal axis on a logarithmic scale) for the three example thyristors. The leakage current for each example thyristor is shown as approximately 1E-11 Amps, as indicated by the vertical portion of the graphs  1601 ,  1701  and  1801 . The point at which the graphs  1601 ,  1701  and  1801  turn almost horizontal represents the point at which the example thyristor becomes damaged, i.e., the leakage current increases significantly. For the third (6×6) example thyristor, for example, the current at which the thyristor became damaged was about 7.8 Amps (indicated by horizontal dashed line  1804 ), which is a relatively large current for this type of device. The maximum current density (Jmax) at this point can then be calculated based on the above mentioned dimensions of the third example thyristor. Similar calculations can be made for the first and second example thyristors. 
     With the data shown by the graphs  1601 ,  1602 ,  1701 ,  1702 ,  1801  and  1802  and the above mentioned dimensions, it is shown or calculated that the example thyristor devices exhibited maximum current density (Jmax) capabilities of more than 3 mA/μm2, which is very robust for SOI technology. For example, the Jmax for the first example thyristor device is about 3.021 mA/μm2, the Jmax for the second example thyristor device is about 3.107 mA/μm2, and the Jmax for the third example thyristor device is about 3.310 mA/μm2. The maximum current density results for the larger example thyristor devices are slightly higher than those for the smaller example thyristor devices, which is the opposite of the proportionality relationship for conventional thyristor devices (wherein larger conventional thyristor devices typically exhibit smaller maximum current densities due to current crowding effects, particularly in SCR configurations). In other words, the robustness of the structure was slightly greater for the larger structures. Additionally, the example thyristors exhibited relatively uniform current capabilities, which is highly significant for ESD protection for an SOI-based device. The direct proportionality relationship between the size of the example thyristor devices and the maximum current density is, thus, an unexpected result. Additionally, with this data and information, it is further shown or calculated that the example thyristor devices exhibited relatively low on resistance (Ron) for the given footprint dimensions, or device sizes. For example, the Ron for the first example thyristor device is about 1.445Ω, the Ron for the second example thyristor device is about 0.975Ω, and the Ron for the third example thyristor device is about 0.616Ω. It is thus shown that thyristor devices formed with a plurality of the thyristor tiles  200  have excellent, and in some cases better than expected, performance characteristics. 
       FIG. 19  shows the simplified schematic diagram of the thyristor  100  of  FIG. 1 , but with optional trigger elements (e.g., NMOS trigger elements  1901 - 1905 ), with connections shown in dashed lines for various embodiments. Although all of the optional trigger elements  1901 - 1905  are shown in the same drawing, it is understood, however, that not all would be used at the same time. For example, the optional trigger element  1901  is a “top” trigger connected between the P-type emitter  103  and the P-type base/collector  107 / 108 . The optional trigger element  1902  is a “middle” trigger connected between the P-type base/collector  107 / 108  and the N-type base/collector  105 / 106 . The optional trigger element  1903  is a “bottom” trigger connected between the N-type base/collector  105 / 106  and the N-type emitter  104 . The optional trigger element  1904  is an NMOS based electrostatic discharge (ESD) protection diode for use in some embodiments with the top trigger element  1901  and is connected between the N-type emitter  104  and the P-type base/collector  107 / 108 . The optional trigger element  1905  is an NMOS based ESD diode for use in some embodiments with the bottom trigger element  1903  and is connected between the P-type emitter  103  and the N-type base/collector  105 / 106 . The NMOS based ESD diode trigger elements  1904  and  1905  enable bidirectionality for the thyristor. Additionally, instead of the NMOS trigger elements shown, alternative embodiments may use any appropriate trigger elements, such as a chain of forward biased diodes (e.g., with each diode providing about 0.7 volts, which can be stacked depending on design requirements) or one or more Zener diodes. Some of these types of trigger elements are difficult to implement in a bulk semiconductor design, but the design of the thyristor  100  enables tremendous flexibility in the use of any of these types of trigger elements in a bulk implementation or SOI implementation. Furthermore, although not shown, some of the trigger elements may be provided with resistors (e.g., between the bases and emitters of the thyristor  100 ) to enable turning off the thyristor  100  and fine tuning of the trigger parameters. 
       FIGS. 20-25  show simplified current-voltage (I-V) graphs  2000 ,  2100 ,  2200 ,  2300 ,  2400  and  2500  indicating the performance of an example horizontal or lateral thyristor device formed with a plurality of the thyristor tiles (e.g., each similar to the thyristor tile  200 ) in an SCR configuration and with or without different ones or combinations of the trigger elements  1901 - 1905  ( FIG. 19 ), in accordance with some embodiments. Each graph  2000 - 2500 , thus, corresponds to a different trigger configuration.  FIG. 26  shows all of the I-V graphs  2000 - 2500  together for comparison. The I-V graphs  2000 - 2500  are provided with a logarithmic scale for the current (ID) and a linear scale for the voltage (VD) and were generated with a DC I-V sweep from about 0-1 volts to about 12-15 volts. 
     The I-V graph  2000  was generated with an example thyristor device not using any of the trigger elements  1901 - 1905 . The I-V graph  2100  was generated with an example thyristor device using only the top trigger element  1901 . The I-V graph  2200  was generated with an example thyristor device using the top trigger element  1901  in combination with the NMOS based ESD diode trigger element  1904 . The I-V graph  2300  was generated with an example thyristor device using only the middle trigger element  1902 . The I-V graph  2400  was generated with an example thyristor device using only the bottom trigger element  1903 . The I-V graph  2500  was generated with an example thyristor device using the bottom trigger element  1903  in combination with the NMOS based ESD diode trigger element  1905 . The I-V graphs  2000 - 2500  demonstrate that the thyristor performs very similarly with each trigger configuration up to about 12 volts. The I-V graphs  2000 - 2500  in  FIGS. 20-26 , thus, demonstrate that the thyristor devices formed with a plurality of the thyristor tiles  200  can be implemented with the trigger elements  1901 - 1905 , as needed to control the trigger voltage, with excellent results. 
       FIG. 27  shows a simplified flowchart for a process  2700  for forming the thyristor devices with the thyristor tiles  200 , in accordance with one or more example embodiments. The particular steps, combination of steps, and order of the steps are provided for illustrative purposes only. Other processes with different steps, combinations of steps, or orders of steps can also be used to achieve the same or similar result. Features or functions described for one of the steps may be performed in a different step in some embodiments. Furthermore, additional steps not explicitly shown or described may be performed before or after or as a sub-portion of the steps shown. Additionally, the above description of the thyristor device (e.g., with the thyristor tiles  200  and the electrical interconnect or metal layers  800 ,  900 ,  1000  and  1100 ) and the following process  2700  for the formation thereof illustrate that, in some embodiments, the thyristor device can be formed as part of or within an overall CMOS process flow without the use of additional masks or changes to the conventional process flow. Thus, the thyristor device can be formed along with or simultaneously with MOSFET devices (or portions thereof) of the overall electronic circuit or integrated circuit. The ability to be formed as part of a conventional CMOS process flow provides a significant advantage (over many prior art thyristor designs and formation processes) for incorporating the thyristor device into the overall electronic circuit or integrated circuit. For example, the lack of additional masks or process changes means that the inclusion of the thyristor device in the overall electronic circuit does not require any additional costs or fabrication time. 
     Upon starting, a semiconductor wafer is provided (at  2701 ). In some embodiments, the semiconductor wafer is already a fully formed SOI wafer at this point. In some embodiments, the semiconductor wafer is a bulk semiconductor wafer, i.e., without a buried oxide of an SOI wafer. In some embodiments, providing the semiconductor wafer at  2701  includes forming a buried oxide layer (e.g., for the BOX layer  301  in  FIGS. 3 and 4 ) on a substrate (e.g., the underlying substrate  302  in  FIGS. 3 and 4 ) and forming a semiconductor layer (e.g., an intrinsic layer, N-minus layer, or P-minus layer into and onto which the above described active layer is to be formed) on the buried oxide layer (e.g., by epitaxial growth or layer transfer techniques), thereby forming an SOI wafer. 
     Some of the subsequent structure formation steps are performed, for example, by patterning a photoresist over the semiconductor layer and implanting dopants of the appropriate N and P conductivity to form the active region of the thyristor tile  200 . Additionally, these formation steps can be performed in conjunction with forming other structures or components (e.g., of MOSFETs) of the overall electronic circuit or integrated circuit of which the resulting horizontal or lateral thyristor device is a part. 
     At  2702 , to begin forming the active region, an N-well is formed as a base region (e.g., the N-well base regions  201   d  and  202   d  in  FIGS. 2-4 ) in the semiconductor layer for the PNP tiles  201  and  202 . At  2703 , a P-well is formed as a base region (e.g., the P-well base regions  203   d  and  204   d  in  FIGS. 2-4 ) in the semiconductor layer for the NPN tiles  203  and  204 . Alternatively, (at  2701 - 2703 ) one of the two wells (N-well or P-well) is provided or formed as an initial N-minus or P-minus epitaxial layer (e.g., as the semiconductor layer on top of the BOX layer  301 ) that also forms a semiconductor layer into and onto which the MOSFETs of the overall electronic circuit are also formed. The other of the two wells is then formed by appropriate implantation of the opposite P or N type dopant. 
     At  2704 , regions of the field oxide  303  are formed on the active region of the thyristor tile  200 . Additionally, areas of the field oxide  303  are removed from portions of locations where the emitter regions  201   a,    202   a,    203   a  and  204   a  and the base/collector regions  201   b/c,    202   b/c,    203   b/c  and  204   b/c  (or the connector regions associated therewith) will be, so that subsequent processing steps can implant or deposit dopants or materials through these openings in the field oxide  303 . 
     At  2705 , N-type regions (e.g., for the N-type base/collector regions  201   b/c  and  202   b/c  and the N-type emitter regions  203   a  and  204   a  in  FIGS. 2-4 ) are formed by N dopant implantation within the N-well and P-well base regions  201   d,    202   d,    203   d  and  204   d,  e.g., at the appropriate removed portions of the field oxide  303 . At  2706 , N+ regions (e.g., for the N+ base/collector connector regions, such as  202   j/k,  and the N+ emitter connector region, such as  204   i ) are formed by additional N dopant implantation within the N-type base/collector regions  201   b/c  and  202   b/c  and the N-type emitter regions  203   a  and  204   a.    
     At  2707 , P-type regions (e.g., for the P-type base/collector regions  203   b/c  and  204   b/c  and the P-type emitter regions  201   a  and  202   a  in  FIGS. 2-4 ) are formed by P dopant implantation within the N-well and P-well base regions  201   d,    202   d,    203   d  and  204   d,  e.g., at the appropriate removed portions of the field oxide  303 . At  2708 , P+ regions (e.g., for the P+ base/collector connector regions, such as  204   j/k,  and the P+ emitter connector region, such as  201   i  and  202   i ) are formed by additional P dopant implantation within the P-type base/collector regions  203   b/c  and  204   b/c  and the P-type emitter regions  201   a  and  202   a.    
     At  2709 , electrically conductive material (e.g., metals, etc.) can be deposited to form the emitter and base/collector contacts  201   e/f/g,    202   e/f/g,    203   e/f/g  and  204   e/f/g  on the connector regions (such as  201   i,    202   i/j/k,    204   i/j/k,  and others not shown or labeled in the drawings). At  2710 , the series of alternating insulator layers (with electrically conductive vias therethrough, e.g., as shown in  FIGS. 9-11 ) and electrically conductive interconnect layers (e.g., the electrical interconnect or metal layers  800 ,  900 ,  1000  and  1100 , as shown in  FIGS. 8-11 ) are formed, thereby electrically connecting the thyristor tiles  200  through the contacts  201   e/f/g,    202   e/f/g,    203   e/f/g  and  204   e/f/g  to the other structures or components of the overall electronic circuit or integrated circuit of which the resulting horizontal or lateral thyristor device is a part. The overall electronic circuit or integrated circuit is further processed into an integrated circuit package. 
     Reference has been made in detail to embodiments of the disclosed invention, one or more examples of which have been illustrated in the accompanying figures. Each example has been provided by way of explanation of the present technology, not as a limitation of the present technology. In fact, while the specification has been described in detail with respect to specific embodiments of the invention, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing, may readily conceive of alterations to, variations of, and equivalents to these embodiments. For instance, features illustrated or described as part of one embodiment may be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present subject matter covers all such modifications and variations within the scope of the appended claims and their equivalents. These and other modifications and variations to the present invention may be practiced by those of ordinary skill in the art, without departing from the scope of the present invention, which is more particularly set forth in the appended claims. Furthermore, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only, and is not intended to limit the invention.