Abstract:
An integrated circuit comprises a first source, a first drain and a first gate that is arranged between the first source and the first drain. A first body is arranged in the first source. An edge of the first body is substantially aligned with the first gate.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation of U.S. patent application Ser. No. 10/691,237 filed on Oct. 22, 2003. The disclosures of the above application is incorporated herein by reference in its entirety. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to transistor structures, and more particularly to transistor structures with reduced chip area.  
       BACKGROUND OF THE INVENTION  
       [0003]     Integrated circuits or chips may include a large number of interconnected transistors. The transistors and other circuit elements are interconnected in various ways to provide desired circuit functions. It is usually most efficient to fabricate multiple integrated circuits on a single wafer. After processing, the integrated circuits that are fabricated on the wafer are separated and then packaged. The wafer can accommodate a fixed number of integrated circuits for a given integrated circuit size. Reducing the size of individual transistors in the integrated circuit may help to reduce the overall size of the integrated circuit. This, in turn, allows an increased number of integrated circuits or chips to be made on each wafer and reduces the cost of the integrated circuits.  
         [0004]     Referring now to  FIGS. 1 and 2 , an exemplary transistor  10  includes a drain  12 , a gate  14 , a source  16  and a body  18  or substrate tap. For example, the transistor  10  in  FIG. 1  is an NMOS transistor. In some circumstances, the body  18  is connected to the source  16  as shown in  FIG. 2 .  
         [0005]     Referring now to  FIG. 3 , the body  18  includes a p +  region and may include a contact tap  30 . The source  16  includes an n +  region and may include a contact tap  32 . The drain  12  includes an n +  region and may include a contact tap  34 . Additional transistors may be fabricated on one or sides of the transistor  10  as indicated by “ . . . ” in  FIG. 3 .  
         [0006]     Referring now to  FIG. 4 , the body  18  may be repeated between sources  16  of adjacent transistors. The body  18  takes up valuable chip area and increases the size of the transistor and the integrated circuit. Additional transistors can be arranged on one or more sides of the transistor  10  as shown by “ . . . ” in  FIG. 4 .  
       SUMMARY OF THE INVENTION  
       [0007]     An integrated circuit comprises a first source, a first drain, and a first gate that is arranged between the first source and the first drain. A first body is arranged in the first source. An edge of the first body is substantially aligned with the first gate.  
         [0008]     In other features, the first source and the first drain include n+ regions and the first body includes a p+ region. The first body tapers as a distance between a midportion of the first body and the first gate decreases. The first body has substantially at least one of a diamond shape, a circular shape, an elliptical shape, a hexagon shape, an octagon shape and a football shape.  
         [0009]     In other features, a second gate is arranged between the first source and the second drain. The first and second gates are connected.  
         [0010]     An integrated circuit comprises a first source, a first drain, and a first gate that is arranged between the first source and the first drain. A first body is arranged in the first source. A second gate is arranged between the first source and the second drain. The first body includes a body contact tap. The first and second gates are arranged farther apart adjacent to the body contact tap than in areas that are not adjacent to the body contact tap. An edge of the first body is substantially aligned with the first gate.  
         [0011]     In other features, the first body includes a body contact tap and wherein the first and second gates are arranged farther apart adjacent to the body contact tap than in areas that are not adjacent to the body contact tap. The first source includes a source contact tap. The first and second gates are arranged farther apart adjacent to the source contact tap than in areas that are not adjacent to the source contact tap. The first body includes a body contact tap. The first and second gates are arranged farther apart adjacent to the body contact tap than in areas that are not adjacent to the body contact tap. The first source, the first drain, and the second drain include n+ regions and the first body includes a p+ region. The first body tapers as a distance between a midportion of the first body and the first gate decreases. The first body has substantially at least one of a diamond shape, a circular shape, an elliptical shape, a hexagon shape, an octagon shape and a football shape.  
         [0012]     An integrated circuit comprises a first source, a first drain, a first gate that is arranged between the first source and the first drain, and a first body that is arranged in the first source. A second gate is arranged between the first source and the second drain. The first source includes a source contact tap. The first and second gates are arranged farther apart adjacent to the source contact tap than in areas that are not adjacent to the source contact tap. An edge of the first body is substantially aligned with the first gate.  
         [0013]     In other features, the first source includes a source contact tap. The first and second gates are arranged farther apart adjacent to the source contact tap than in areas that are not adjacent to the source contact tap. The first source, the first drain, and the second drain include n+ regions and the first body includes a p+ region. The first body tapers as a distance between a midportion of the first body and the first gate decreases. The first body has at least one of a diamond shape, a circular shape, an elliptical shape, a hexagon shape, an octagon shape and a football shape. The first and second gates are connected.  
         [0014]     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0016]      FIG. 1  is an electrical symbol for a transistor with a drain, source, gate and body according to the prior art;  
         [0017]      FIG. 2  is an electrical symbol for a transistor with a drain, source, gate and body, which is connected to the source according to the prior art;  
         [0018]      FIG. 3  is an exemplary layout of the transistor of  FIG. 2  according to the prior art;  
         [0019]      FIG. 4  is an exemplary layout of multiple transistors that are arranged in a row according to the prior art;  
         [0020]      FIG. 5A  is a first exemplary layout of transistors including a body that is arranged in the source;  
         [0021]      FIG. 5B  is a second exemplary layout of transistors including a body having edges that align with the gates in plan view;  
         [0022]      FIG. 6  is a second exemplary layout of transistors including a body that is arranged in the source;  
         [0023]      FIG. 7  is a third exemplary layout of transistors including a body that is arranged in the source;  
         [0024]      FIG. 8  is a fourth exemplary layout of transistors including a body that is arranged in the source; and  
         [0025]      FIG. 9  is a fifth exemplary layout of transistors including a body that is arranged in the source. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]     The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. For purposes of clarity, the same reference numbers will be used in the drawings to identify the same elements. Additional transistors can be arranged on one or more sides of the illustrated transistors that are shown in the FIGS. as indicated by “ . . . ” in the FIGS.  
         [0027]     Referring now to  FIGS. 5A and 5B , a transistor  50  according to the present invention is shown to include one or more sources  54  and one or more drains  56 . The sources  54  and the drains  56  include n +  regions. While an NMOS transistor is shown, skilled artisans will appreciate that the present invention also applies to other types of transistors such as PMOS transistors. Gates  58  are located between adjacent pairs of sources  54  and drains  56 . In one implementation, the gates  58  that are located on opposite sides of the sources  54  are connected together as shown at  64 . In other configurations, however, the gates  58  need not be connected together.  
         [0028]     A body  66  including a p +  region is arranged inside of and is surrounded by the source  54 . The body  66  preferably has a shape that tapers as a distance between a midportion of the body  66  and adjacent gates decreases. The body  66  may touch or not touch the gates  58  in the plan views of  FIGS. 5A  and  5 B. In other words, one or both edges of the body  66  may be spaced from the gates  58  in plan view (as shown in  FIG. 5A ) and/or substantially aligns with the gates in plan view (as shown in  FIG. 5B ). By utilizing some of the area of the source  54  for the body  66 , the overall size of the transistor  50  is reduced as compared to conventional transistors. In the exemplary implementation that is shown in  FIG. 5 , the body  66  has a diamond shape.  
         [0029]     Referring now to  FIGS. 6 and 7 , other exemplary shapes for the body  66  are shown. In  FIG. 6 , the body  66  has a hexagon shape. In  FIG. 7 , the body is generally football shaped. Skilled artisans will appreciate that there are a wide variety of other suitable shapes. For example, a circular body is shown in  FIG. 8 , which is described. Other suitable shapes include an ellipse, an octagon, etc.  
         [0030]     Referring now to  FIGS. 8 and 9 , the gates  58  can be arranged such that they are closer together when there are no contact taps and further apart when there are contact taps. In  FIG. 8 , a source contact tap  70 , which is not located in the body  66 , is located in a region where the adjacent gates  58  are located farther apart. In  FIG. 9 , a body contact tap  80 , which is located in the body  66 , is located in the source  54  where the adjacent gates  58  are located farther apart.  
         [0031]     Those skilled in the art can now appreciate from the foregoing description that the broad teachings of the present invention can be implemented in a variety of forms. Therefore, while this invention has been described in connection with particular examples thereof, the true scope of the invention should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, the specification and the following claims.