Abstract:
This invention provides a memory structure and an operation method thereof. The memory structure includes a triode for alternating current (TRIAC) and a memory cell. The memory cell is electrically connected to the TRIAC.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Taiwan application serial no. 103114245, filed on Apr. 18, 2014. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
     FIELD OF THE DISCLOSURE 
     The disclosure relates to a memory structure and an operation method thereof. More particularly, the disclosure relates to a memory structure having a triode for alternating current and an operation method thereof. 
     DESCRIPTION OF RELATED ART 
     Memory structures composed of memory cells and diodes have been developed in the related art. Taking a magnetoresistance random access memory cell (MRAM) as an example, the MRAM is composed of a MRAM cell and a diode and capable of executing non-volatile memory operation. The MRAM cell is used for storing data. The diode of the MRAM serves as a selective device, used for preventing the MRAM cell from being affected by other MRAM cells of the MRAM cell array. MRAMs have advantages such as high speed, low power consumption and high level of integration. 
     However, in the memory array structure which is composed of memory cells and diodes, when the selected memory cell perforans operations like writing, erasing, reading or the like, disturbance may still cause to the other non-selected memory cells, resulting in the wrong writing, erasing of the non-selected memory cell, or the wrong reading of the selected memory cell. 
     SUMMARY OF THE DISCLOSURE 
     The disclosure provides a memory structure which has superior electrical characteristic. 
     The disclosure provides an operation method of a memory structure which can use a triode for alternating current to operate the memory structure. 
     The disclosure proposes a memory structure including a triode for alternating current (TRIAC) and a memory cell. The memory cell is electrically connected to the triode for alternating current (TRIAC). 
     According to one exemplary embodiment of the disclosure, in the memory structure, the memory cell is a bidirectional operation memory cell or a unidirectional operation memory cell, for example. 
     According to one exemplary embodiment of the disclosure, in the memory structure, the TRIAC includes a first terminal, a semiconductor layer, a second terminal and a gate electrode. The semiconductor layer is disposed on the first terminal and includes a first doped layer, a second doped layer, a third doped layer, a first doped region, a second doped region and a third doped region. The first doped layer, the second doped layer and the third doped layer are disposed sequentially on the first terminal. The first doped region is disposed in the first doped layer. The second doped region and the third doped region are disposed separately in the third doped layer. The first doped layer and the third doped layer are a first conductive type, the second doped layer, the first doped region, the second doped region and the third doped region are a second conductive type, and the first conductive type and the second conductive type are different conductive types. The first terminal is electrically connected to the first doped layer and the first doped region. The second terminal is disposed on the semiconductor layer and electrically connected to the third doped layer and the second doped region. The gate electrode is disposed on the semiconductor layer and electrically connected to the third doped layer and the third doped region. 
     According to one exemplary embodiment of the disclosure, in the memory structure, the first conductive type is one of the P-type and the N-type, and the second conductive type is the other one of the P-type and the N-type. 
     According to one exemplary embodiment of the disclosure, in the memory structure, the second terminal is the conductive layer of the memory cell, for example. 
     According to one exemplary embodiment of the disclosure, in the memory structure, the second doped region is located on the upper surface of the third doped layer, the third doped region is located on the side surface of the third doped layer, and the upper surface of the third doped region is lower than the upper surface of the second doped region, for example. 
     According to one exemplary embodiment of the disclosure, in the memory structure, both of the second doped region and the third doped region are located on the upper surface of the third doped layer, for example. 
     According to one exemplary embodiment of the disclosure, the memory structure further includes a first conductive line electrically connected to the first terminal. 
     According to one exemplary embodiment of the disclosure, the memory structure further includes a conductive layer electrically connected to the second terminal via the memory cell. 
     According to one exemplary embodiment of the disclosure, the memory structure further includes a second conductive line electrically connected to the conductive layer. 
     According to one exemplary embodiment of the disclosure, the memory structure further includes a third conductive line electrically connected to the gate electrode. 
     The disclosure provides an operation method of a memory structure, wherein the memory structure includes a TRIAC, a memory cell and a conductive layer. The TRIAC includes a first terminal, a second terminal and a gate electrode. The conductive layer is electrically connected to the second terminal via the memory cell. The operation method of the memory structure includes performing a write operation on the memory cell, including the following steps. The fourth voltage is applied to the first terminal. The second voltage is applied to the conductive layer. The third voltage is applied to the gate electrode. Herein the voltage difference between the first voltage and the second voltage is not 0, and a first current which passes through the memory cell is generated. The third voltage is higher than one of the first voltage and the second voltage. 
     According to one exemplary embodiment of the disclosure, the operation method of the memory structure further includes performing an erase operation on the memory cell, including the following steps. The fourth voltage is applied to the first terminal. The fifth voltage is applied to the conductive layer. The sixth voltage is applied to the gate electrode. Herein the voltage difference between the fourth voltage and the fifth voltage is not 0, and a second current which passes through the memory cell is generated. The sixth voltage is higher than one of the fourth voltage and the fifth voltage. When the first voltage is higher than the second voltage, the fourth voltage is lower than the fifth voltage. When the first voltage is lower than the second voltage, the fourth voltage is higher than the fifth voltage. 
     According to one exemplary embodiment of the disclosure, the operation method of the memory structure further includes performing a read operation on the memory cell, including the following steps. The seventh voltage is applied to the first terminal. The eighth voltage is applied to the conductive layer. The ninth voltage is applied to the gate electrode. Herein the voltage difference between the seventh voltage and the eighth voltage is not 0, and a third current which passes through the memory cell is generated. The seventh voltage is higher than one of the first voltage and the second voltage and lower than the other one of the first voltage and the second voltage. The ninth voltage is higher than one of the seventh voltage and the eighth voltage. 
     The disclosure provides another operation method of a memory structure, wherein the memory structure includes a plurality of first conductive lines, a plurality of second conductive lines, a plurality of third conductive lines, a plurality of memory cells and a plurality of TRIACs. Each of the TRIACs includes a first terminal, a second terminal and a gate electrode. Herein the first conductive line is electrically connected to the first terminal, the second conductive line is electrically connected to the second terminal via the memory cell, and the third conductive line is electrically connected to the gate electrode. The operation method of the memory structure includes performing a write operation on the selected memory cell, including the following steps. The first voltage is applied to the first conductive line which is electrically connected to the selected memory cell. The second voltage is applied to the second conductive line which is electrically connected to the selected memory cell. The third voltage is applied to the third conductive line which is electrically connected to the selected memory cell. Herein the voltage difference between the first voltage and the second voltage is not 0, and a first current which passes through the selected memory cell is generated. The third voltage is higher than one of the first voltage and the second voltage. 
     According to one exemplary embodiment of the disclosure, in the operation method of the memory structure, the step of performing a write operation includes the following steps. The fourth voltage is applied to the first conductive line which is electrically connected to the non-selected memory cell. The fifth voltage is applied to the second conductive line which is electrically connected to the non-selected memory cell. The sixth voltage is applied to the third conductive line which is electrically connected to the non-selected memory cell. Herein the third voltage is higher than the sixth voltage. The voltage difference between the fourth voltage and the fifth voltage is generally smaller than the voltage difference between the first voltage and the second voltage. 
     According to one exemplary embodiment of the disclosure, the operation method of the memory structure further includes performing an erase operation on the selected memory cell, including the following steps. The seventh voltage is applied to the first conductive line which is electrically connected to the selected memory cell. The eighth voltage is applied to the second conductive line which is electrically connected to the selected memory cell. The ninth voltage is applied to the third conductive line which is electrically connected to the selected memory cell. Herein the voltage difference between the seventh voltage and the eighth voltage is not 0, and a second current which passes through the selected memory cell is generated. The ninth voltage is higher than one of the seventh voltage and the eighth voltage. When the first voltage is higher than the second voltage, the seventh voltage is lower than the eighth voltage. When the first voltage is lower than the second voltage, the seventh voltage is higher than the eighth voltage. 
     According to one exemplary embodiment of the disclosure, in the operation method of the memory structure, the step of performing an erase operation includes the following steps. The tenth voltage is applied to the first conductive line which is electrically connected to the non-selected memory cell. The eleventh voltage is applied to the second conductive line which is electrically connected to the non-selected memory cell. The twelfth voltage is applied to the third conductive line which is electrically connected to the non-selected memory cell. Herein the ninth voltage is lower than the twelfth voltage. The voltage difference between the tenth voltage and the eleventh voltage is generally smaller than the voltage difference between the second voltage and the eighth voltage. 
     According to one exemplary embodiment of the disclosure, the operation method of the memory structure further includes performing a read operation on the selected memory cell, including the following steps. The thirteenth voltage is applied to the first conductive line which is electrically connected to the selected memory cell. The fourteenth voltage is applied to the second conductive line which is electrically connected to the selected memory cell. The fifteenth voltage is applied to the third conductive line which is electrically connected to the selected memory cell. Herein the voltage difference between the thirteenth voltage and the fourteenth voltage is not 0, and a third current which passes through the selected memory cell is generated. The thirteenth voltage is higher than one of the first voltage and the second voltage and generally lower than the other one of the first voltage and the second voltage. The fifteenth voltage is higher than one of the thirteenth voltage and the fourteenth voltage and lower than the other one of the thirteenth voltage and the fourteenth voltage. 
     According to one exemplary embodiment of the disclosure, in the operation method of the memory structure, the step of performing a read operation includes the following steps. The sixteenth voltage is applied to the first conductive line which is electrically connected to the non-selected memory cell. The seventeenth voltage is applied to the second conductive line which is electrically connected to the non-selected memory cell. The eighteenth voltage is applied to the third conductive line which is electrically connected to the non-selected memory cell. Herein the fifteenth voltage is higher than the eighteenth voltage. The voltage difference between the sixteenth voltage and the seventeenth voltage is generally smaller than the voltage difference between the thirteenth voltage and the fourteenth voltage. 
     In light of the above, the memory structure provided by the disclosure uses the TRIAC as a switch, and thus has superior electrical characteristic. In addition, in the operation method of the memory structure of the disclosure, operation may be performed on the memory structure by using the TRIAC. 
     To make the above features and advantages of the disclosure more comprehensible, several embodiments accompanied with drawings are described in detail as follows. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
         FIG. 1A  is a cross-sectional view of a memory structure according to an embodiment of the disclosure. 
         FIG. 1B  is a perspective view of  FIG. 1A . 
         FIG. 1C  is a schematic view showing that a write operation is performed on the memory structure of  FIG. 1A . 
         FIG. 1D  is a schematic view showing that an erase operation is performed on the memory structure of  FIG. 1A . 
         FIG. 1E  is a schematic view showing that a read operation is performed on the memory structure of  FIG. 1A . 
         FIG. 2A  is a cross-sectional view of a memory structure according to another embodiment of the disclosure. 
         FIG. 2B  is a perspective view of  FIG. 2A . 
         FIG. 3A  is a schematic circuit diagram of performing a write operation on the memory structure. 
         FIG. 3B  is a schematic circuit diagram of performing an erase operation on the memory structure. 
         FIG. 3C  is a schematic circuit diagram of performing a read operation on the memory structure. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
       FIG. 1A  is a cross-sectional view of a memory structure according to an embodiment of the disclosure.  FIG. 1B  is a perspective view of  FIG. 1A .  FIG. 1C  is a schematic view showing that a write operation is performed on the memory structure of  FIG. 1A .  FIG. 1D  is a schematic view showing that an erase operation is performed on the memory structure of  FIG. 1A .  FIG. 1E  is a schematic view showing that a read operation is performed on the memory structure of  FIG. 1A . 
     Referring to  FIG. 1A  and  FIG. 1B , the memory structure  10  includes a TRIAC  102  and a memory cell  104 . The memory cell  104  is electrically connected to the TRIAC  102 . The TRIAC  102  may be disposed on the substrate  100 , and the memory cell  104  may be disposed on the TRIAC  102 . The substrate  100  is, for example, a silicon substrate. In another embodiment, the TRIAC  102  may also be disposed on the metal dielectric layer of the back-end semiconductor process. The memory cell  104  is a bidirectional operation memory cell or a unidirectional operation memory cell, for example, such as magnetoresistance random access memory cell (MRAM), resistive random access memory cell, or the like, but the disclosure is not limited thereto, the memory cell  104  in which as long as the TRIAC  102  is used as a switch belongs to the scope of the claimed invention. 
     For instance, the memory cell  104  is a spin-transfer torque magnetic random access memory cell (STT-MRAM cell), and includes a free magnetic layer  106 , an insulating layer  108  and a fixed magnetic layer  110  which are stacked and disposed. The fixed magnetic layer  110  has a fixed magnetization vector or a fixed total magnetic moment in a predetermined direction. Since the magnetization direction of the free magnetic layer  106  may be reversed, the magnetic memory cell  104  may be parallel or anti-parallel to the magnetization direction of the fixed magnetic layer  110  through the free magnetic layer  106  of the two sides of the insulating layer  108 , in order to determine storing a data of “0” or “1”. The operating details of the STT-MRAM cell and the material of each of the film layers are well-known for persons ordinarily skilled in the art, thus the descriptions are omitted herein. 
     The TRIAC  102  includes a terminal  112 , a semiconductor layer  114 , a terminal  116  and a gate electrode  118 . The terminal  112  may be disposed on the substrate  100 . In another embodiment, the terminal  112  may also be disposed on the metal dielectric layer of the back-end semiconductor process. The material of the terminal  112  is, for example, a conductive material, such as copper, tungsten, or aluminum, so forth. The memory structure  10  may further include a conductive line  120 , and the conductive line  120  is electrically connected to the terminal  112  and used for applying voltage to the terminal  112 . In the present embodiment, the conductive line  120  acts as a source line, for example. The terminal  112  is a portion of the conductive line  120 , for example, but the disclosure is not limited thereto. In other embodiments, the terminal  112  may also be another conductive component which is separated from the conductive line  120 , as long as the terminal  112  may be electrically connected to the doped layer  122  and the doped region  128 . 
     The semiconductor layer  114  is disposed on the terminal  112  and includes a doped layer  122 , a doped layer  124 , a doped layer  126 , a doped region  128 , a doped region  130  and a doped region  132 . The material of the semiconductor layer  114  is, for example, poly-silicon. Herein the doped layer  122 , the doped layer  124  and the doped layer  126  are disposed sequentially on the terminal  112 . The doped region  128  is disposed in the doped layer  122 . The doped region  130  and the doped region  132  are disposed separately in the doped layer  126 . The doped region  130  is located on the upper surface of the doped layer  126 , for example, the doped region  132  is located on the side surface of the doped layer  126 , and the upper surface of the doped region  132  is lower than the upper surface of the doped region  130 . In the present embodiment, the doped region  128  and the doped region  132  being located on the different sides of the semiconductor layer  114  is illustrated as an example, however the disclosure is not limited thereto. In other embodiments, the doped region  128  and the doped region  132  may also be located on the same side of the semiconductor layer  114 . 
     The doped layer  122  and the doped layer  126  are the first conductive type, the doped layer  124 , the doped region  128 , the doped region  130  and the doped region  132  are the second conductive type, and the first conductive type and the second conductive type are different conductive types. The first conductive type may be one of the P-type and the N-type, and the second conductive type is the other one of the P-type and the N-type. In the present embodiment, as exemplarily illustrated, the first conductive type is the P-type and the second conductive type is the N-type. 
     The terminal  116  is disposed on the semiconductor layer  114  and electrically connected to the doped layer  126  and the doped region  130 . The material of the terminal  116  is, for example, a conductive material, such as CoFeB. In the present embodiment, the terminal  116  is, for example, the conductive layer of the memory cell  104 , such as the free magnetic layer  106 . Namely, the TRIAC  102  may use the free magnetic layer  106  of the memory cell  104  as the terminal  116 , but the disclosure is not limited thereto. In other embodiments, the terminal  116  may also be another conductive component which is separated from the memory cell  104 , as long as the terminal  116  may be electrically connected to the doped layer  126  and the doped region  130 . 
     Additionally, the memory structure  10  may further include a conductive layer  134 , and the conductive layer  134  is electrically connected to the terminal  116  via the memory cell  104  and used for applying voltage to the memory cell  104  and the terminal  112 . The material of the conductive layer  134  is, for example, a conductive material, such as copper, tungsten, or aluminum, so forth. In addition, the memory structure  10  may further include a conductive line  136 , and the conductive line  136  is electrically connected to the conductive layer  134 . In the present embodiment, the conductive line  136  acts as a bit line, for example. The conductive layer  134  is a portion of the conductive line  136 , for example, but the disclosure is not limited thereto. In other embodiments, the conductive layer  134  may also be another conductive component which is separated from the conductive line  136 , as long as the terminal  134  may be electrically connected to the memory cell  104  and the TRIAC  102 . 
     The gate electrode  118  is disposed on the semiconductor layer  114  and electrically connected to the doped layer  126  and the doped region  132 . In the present embodiment, the gate electrode  118  is disposed on the side surface of the semiconductor layer  114 . The memory structure  10  may further include a conductive line  138 , and the conductive line  138  is electrically connected to the gate electrode  118  and used for applying voltage to the gate electrode  118 . The conductive line  138  is, for example, used as a gate line. The gate electrode  118  is a portion of the conductive line  138 , for example, but the disclosure is not limited thereto. In other embodiments, the gate electrode  118  may also be another conductive component which is separated from the conductive line  138 , as long as the conductive line  138  may apply voltage to the gate electrode  118 . 
     Moreover, referring to  FIG. 1A , the memory structure  10  may further include a dielectric layer  140  which is at least disposed on the two sides of the semiconductor layer  114 , the memory cell  104  and the conductive line  134 , but the disclosure is not limited thereto, and persons ordinarily skilled in the art may adjust the disposing method of the dielectric layer  140  according to the design requirement of the product. In addition, for the sake of clearly illustration of the configuration of each of component of  FIG. 1B , the dielectric layer  140  is omitted in  FIG. 1B . 
     In the following, the operation method of the memory structure  10  through the action mode of the TRIAC  102  is simply illustrated with  FIG. 1A . Referring to  FIG. 1A , the voltage VT 1  is applied to the terminal  112 , the voltage VT 2  is applied to the conductive layer  134 , and the voltage VG is applied to the gate electrode  118 . When the voltage VT 1  applied to the terminal  112  is higher than the voltage VT 2  applied to the conductive layer  134 , the voltage difference between the terminal  112  and the terminal  116  is not 0, and so that the TRIAC  102  generates act. At this time, via the act of the TRIAC  102 , the current may pass from the terminal  112 , through the doped layer  122 , the doped layer  124 , the doped layer  126 , and the doped region  130  along the current direction D 1 , and to the terminal  116 , and the current may pass from the terminal  116  and through the memory cell  104 , and then to the conductive layer  134 . Thus, through the current which passes through the memory cell  104  along the current direction D 1 , operation may be performed on the memory cell  104 . 
     In addition, when the voltage VT 1  applied to the terminal  112  is lower than the voltage VT 2  applied to the conductive layer  134 , the voltage difference between the terminal  112  and the terminal  116  is not 0, and so that the TRIAC  102  generates act. At this time, via the act of the TRIAC  102 , the current may pass from the conductive layer  134 , through the memory cell  104  along the current direction D 2 , and to the terminal  116 , and the current may pass through the doped layer  126 , the doped layer  124 , the doped layer  122 , and the doped region  128 , and then to the terminal  112 . Thus, through the current which passes through the memory cell  104  along the current direction D 2 , operation may be performed on the memory cell  104 . 
     Referring to  FIG. 1C , performing the write operation on the memory cell  104  of the memory structure  10  includes the following steps. The voltage V 1  is applied to the terminal  112 . The voltage V 2  is applied to the conductive layer  134 . The voltage V 3  is applied to the gate electrode  118 . Herein the voltage difference between the voltage V 1  and the voltage V 2  is not 0, and a first current C 1  which passes through the memory cell is generated. The voltage V 3  is higher than one of the voltage V 1  and the voltage V 2 . 
     In the present embodiment, as exemplarily illustrated, the voltage V 1  is 1.2V, the voltage V 2  is 0V, and the voltage V 3  is 0.5V. At this time, with the voltage difference of 1.2V between the voltage V 1  and the voltage V 2 , the TRIAC  102  may be turned on, thus the current C 1  may pass from the terminal  112 , through the doped layer  122 , the doped layer  124 , the doped layer  126 , the doped region  130 , and to the terminal  116 , and the current C 1  may pass from the terminal  116  and through the memory cell  104 , and then to the conductive layer  134 , as such a write operation is performed on the memory cell  104 . Therefore, if the memory cell  104  is a STT-MRAM cell, the magnetoresistance of the memory cell  104  may be changed due to the current C 1  which passes through the memory cell  104 , so as to perform write operation on the memory cell  104  and the “1” data is stored in the memory cell  104 . 
     Referring to  FIG. 1D , performing the erase operation on the memory cell  104  of the memory structure  10  includes the following steps. The voltage V 4  is applied to the terminal  112 . The voltage V 5  is applied to the conductive layer  134 . The voltage V 6  is applied to the gate electrode  118 . Herein the voltage difference between the voltage V 4  and the voltage V 5  is not 0, and a current C 2  which passes through the memory cell  104  is generated. The voltage V 6  is higher than one of the voltage V 4  and the voltage V 5 . When the voltage V 1  is higher than the voltage V 2  in  FIG. 1C , the voltage V 4  is lower than the voltage V 5  in  FIG. 1D . When the voltage V 1  is lower than the voltage V 2  in  FIG. 1C , the voltage V 4  is higher than the voltage V 5  in  FIG. 1D . 
     In the present embodiment, as exemplarily illustrated, the voltage V 4  is 0V, the voltage V 5  is 1.2V, and the voltage V 6  is 0.7V. At this time, with the voltage difference of 1.2V between the voltage V 4  and the voltage V 5 , the TRIAC  102  may be turned on, thus the current C 2  may pass from the conductive layer  134 , through the memory cell  104  and to the terminal  116 , and the current C 2  may pass from the terminal  116  through the doped layer  126 , the doped layer  124 , the doped layer  122 , the doped region  128 , and to the terminal  112 , as such an erase operation is performed on the memory cell  104 . Therefore, if the memory cell  104  is a STT-MRAM cell, the magnetoresistance of the memory cell  104  may be changed due to the current C 2  which passes through the memory cell  104 , so as to perform erase operation on the memory cell  104  and the “0” data is stored in the memory cell  104 . 
     Referring to  FIG. 1E , performing the read operation on the memory cell  104  of the memory structure  10  includes the following steps. The voltage V 7  is applied to the terminal  112 . The voltage V 8  is applied to the conductive layer  134 . The voltage V 9  is applied to the gate electrode  118 . Herein the voltage difference between the voltage V 7  and the voltage V 8  is not 0, and a current C 3  which passes through the memory cell  104  is generated. The voltage V 7  in  FIG. 1E  is higher than one of the voltage V 1  and the voltage V 2  in  FIG. 1C . The voltage V 9  is higher than one of the voltage V 7  and the voltage V 8 . 
     In the present embodiment, as exemplarily illustrated, the voltage V 7  is 1V, the voltage V 8  is 0V, and the voltage V 9  is 0.5V. At this time, with the voltage difference of 1V between the voltage V 7  and the voltage V 8 , the TRIAC  102  may be turned on, thus the current C 3  may pass from the terminal  112 , through the doped layer  122 , the doped layer  124 , the doped layer  126 , the doped region  130 , and to the terminal  116 , and the current C 3  may pass from the terminal  116  and through the memory cell  104 , and then to the conductive layer  134 . Thus, through the current C 3  which passes through the memory cell  104 , the data stored in the memory cell  104  may be read. 
     In the abovementioned embodiment, the memory structure  10  uses the TRIAC  102  as a switch, thus the memory structure  10  has superior electrical characteristic, such as generating leakage current may be suppressed. In addition, when operation is performed on the selected memory cell  104 , the TRIAC  102  of the memory structure  10  may effectively avoid the disturbance generated to the non-selected memory cell  104 . Moreover, if the upper surface of the doped region  132  of the semiconductor layer  114  is lower than the upper surface of the doped region  130  and the gate electrode  118  is disposed on the side surface of the semiconductor layer  114 , the dimension of the memory unit may be effectively reduced and the level of integration of the component may be effectively improved. In addition, in the operation method of the memory structure of the abovementioned embodiment, operation may be performed on the memory structure  10  by using the TRIAC  102 . 
       FIG. 2A  is a cross-sectional view of a memory structure according to another embodiment of the disclosure.  FIG. 2B  is a perspective view of  FIG. 2A . 
     Referring to  FIG. 1A ,  FIG. 1B ,  FIG. 2A  and  FIG. 2B , the difference between the memory structure  20  of  FIG. 2A  and  FIG. 2B  and the memory structure  10  of  FIG. 1A  and  FIG. 1B  is: the doped region  132   a  is located on the upper surface of the doped layer  126  (i.e., both of the doped region  130  and the doped region  132   a  are located on the upper surface of the doped layer  126 ), and the gate electrode  118   a  is disposed on the upper surface of the semiconductor layer  114 . In addition, the arrangements, materials, functions and operation methods of other components of the memory structure  20  are similar to those of the memory structure  10 , and thus no further description is provided hereinafter. In addition, for the sake of clearly illustration of the configuration of each of component of  FIG. 2B , the dielectric layer  140  is omitted in  FIG. 2B . 
     In the abovementioned embodiment, the memory structure  20  uses the TRIAC  102  as a switch, thus the memory structure  20  has superior electrical characteristic, such as generating leakage current may be suppressed. In addition, when operation is performed on the selected memory cell  104 , the TRIAC  102  of the memory structure  20  may effectively avoid the disturbance generated to the non-selected memory cell  104 . 
       FIG. 3A  is a schematic circuit diagram of performing a write operation on the memory structure.  FIG. 3B  is a schematic circuit diagram of performing an erase operation on the memory structure.  FIG. 3C  is a schematic circuit diagram of performing a read operation on the memory structure. 
     The memory structure of  FIG. 3A  through  FIG. 3C  may be the memory structure  10  or the memory structure  20 . In the present embodiment, performing operation on the memory structure  10  is illustrated as an example, each of the components of the memory structure  10  is described in detail in the abovementioned embodiment, and thus no further description is provided hereinafter. In addition, though performing operation on the memory structure  10  is exemplarily illustrated in the operation method of the following embodiment, the operation method is also adapted to performing operation on the memory structure  20 . 
     Referring to  FIG. 1A ,  FIG. 1B ,  FIG. 3A  through  FIG. 3C , the memory structure  10  includes a plurality of conductive lines  120 , a plurality of conductive lines  136 , a plurality of conductive lines  138 , a plurality of memory cells  104  and a plurality of TRIACs  102 . Each of the TRIACs  102  includes a terminal  112 , a terminal  116  and a gate electrode  118 . The conductive lines  120  may form a plurality of source lines SL n , SL n+1 , SL n+2  . . . , the conductive lines  136  may form a plurality of bit lines BL n , BL n+1 , BL n+2  . . . , and the conductive lines  138  may form a plurality of gate lines GL n , GL n+1 , GL n+2  . . . . 
     In the following, the three source lines SL n , SL n+1 , SL n+2 , the three bit lines BL n , BL n+1 , BL n+2 , and the three gate lines GL n , GL n+1 , GL n+2  are exemplarily illustrated. Herein the source lines SL n , SL n+1 , SL n+2  are electrically connected to the terminal  112 , the bit lines BL n , BL n+1 , BL n+2  are electrically connected to the terminal  116 , the gate lines GL n , GL n+1 , GL n+2  are electrically connected to the gate electrode  118 , and a memory array structure is formed. Herein the source lines SL n , SL n+1 , SL n+2  extend along the direction D 3 , and the bit lines BL n , BL n+1 , BL n+2  and the gate lines GL n , GL n+1 , GL n+2  are alternately arranged and extend along the direction D 4 , for example. The direction D 3  intersects the direction D 4 , for example. 
     Referring to  FIG. 3A  through  FIG. 3C , the memory cells  104  may be divided into selected memory cells  104   a , and non-selected memory cells  104   b ,  104   c ,  104   d . Herein the non-selected memory cells  104   b  and the selected memory cells  104   a  do not share the source lines SL n , SL n+1 , SL n+2 , the bit lines BL n , BL n+1 , BL n+2  and the gate lines GL n , GL n+1 , GL n+2 . The non-selected memory cells  104   c  and the selected memory cells  104   a  do not share the bit lines BL n , BL n+1 , BL n+2  and the gate lines GL n , GL n+1 , GL n+2 , and share the source lines SL n , SL n+2 . The non-selected memory cells  104   d  and the selected memory cells  104   a  share the gate line GL n+1  and the bit line BL n+1 , and do not share the source lines SL n , SL n+1 , SL n+2 . 
     Referring to  FIG. 3A , performing the write operation on the selected memory cells  104   a  of the memory structure  10  includes the following steps. The voltage V 10  is applied to the source lines SL n , SL n+2  which are electrically connected to the selected memory cells  104   a . The voltage V 11  is applied to the bit line BL n+1  which is electrically connected to the selected memory cells  104   a . The voltage V 12  is applied to the gate line GL n+1  which is electrically connected to the selected memory cells  104   a . Herein the voltage difference between the voltage V 10  and the voltage V 11  is not 0, and currents C 4  which pass through the selected memory cells  104   a  are generated. The voltage V 12  is higher than one of the voltage V 10  and the voltage V 11 . 
     In the present embodiment, as exemplarily illustrated, the voltage V 10  is 1.2V, the voltage V 11  is 0V, and the voltage V 12  is 0.5V. At this time, with the voltage difference of 1.2 V between the voltage V 10  and the voltage V 11 , the TRIACs  102  which are connected to the selected memory cells  104   a  may be in on-state, thus the current C 4  may pass from the source lines SL n , SL n+2 , through the TRIACs  102  and the selected memory cells  104   a , and to the bit line BL n+1 , and the write operation is performed on the selected memory cells  104   a . Therefore, if the selected memory cells  104  are STT-MRAM cells, the magnetoresistance of the selected memory cells  104   a  may be changed due to the currents C 4  which pass through the selected memory cells  104   a , and the “1” data is stored in the selected memory cells  104   a.    
     In addition, performing a write operation on the memory structure  10  further includes the following steps. The voltage V 13  is applied to the source line SL n+1  which are electrically connected to the non-selected memory cells  104   b . The voltage V 14  is applied to the bit lines BL n , BL n+2  which are electrically connected to the non-selected memory cells  104   b . The voltage V 15  is applied to the gate lines GL n  GL n+2  which are electrically connected to the non-selected memory cells  104   b . Herein the voltage V 12  is higher than the voltage V 15 , the voltage difference between the voltage V 13  and the voltage  14  is generally smaller than the voltage difference between the voltage V 10  and the voltage V 11 , thus the TRIACs  102  may be in off-state. 
     In the present embodiment, as exemplarily illustrated, the voltage V 13  is 0V, the voltage V 14  is 0.6V, and the voltage V 15  is 0.3V. As for the non-selected memory cells  104   b ,  104   c , though there is a voltage difference of 0.6V between the voltage V 13  and the voltage V 14  and between the voltage V 10  and the voltage V 14 , the voltage V 15  (e.g., 0.3V) applied to the gate lines GL n , GL n+2  is lower than the voltage V 12  (e.g., 0.5V) applied to the gate line GL n+1 , and the voltage difference (e.g., 0.6V) between the voltage V 13  and the voltage V 14  and between the voltage V 10  and the voltage V 14  is smaller than the voltage difference (e.g., 1.2V) between the voltage V 10  and the voltage V 11 , due to the currents which pass through the TRIACs  102  connected to the non-selected memory cells  104   b ,  104   c  being extremely tiny, so that the TRIACs  102  connected to the non-selected memory cells  104   b ,  104   c  are in off-state. Therefore, when write operation is performed on the selected memory cells  104   a , disturbance does not cause to the non-selected memory cells  104   b ,  104   c  and write or erase operation is not performed. 
     In the present embodiment, as for the non-selected memory cells  104   d , the voltage difference (e.g., 0V) between the voltage V 13  and the voltage V 11  is smaller than the voltage difference (e.g., 1.2V) between the voltage V 10  and the voltage V 11 , so that the TRIACs  102  connected to the non-selected memory cells  104   d  are in off-state. In the present embodiment, since the voltage values of the voltage V 13  and the voltage V 11  are equal, the voltage difference between the voltage V 13  and the voltage V 11  is 0V. Thus, no current passes through the TRIACs  102  connected to the non-selected memory cells  104   c , namely, the TRIACs  102  connected to the non-selected memory cells  104   d  are in off-state. Therefore, when write operation is performed on the selected memory cells  104   a , disturbance does not cause to the non-selected memory cells  104   d  and write or erase operation is not performed. 
     Referring to  FIG. 3B , performing the erase operation on the selected memory cells  104   a  of the memory structure  10  includes the following steps. The voltage V 16  is applied to the source lines SL n , SL n+2  which are electrically connected to the selected memory cells  104   a . The voltage V 17  is applied to the bit line BL n+1  which is electrically connected to the selected memory cells  104   a . The voltage V 18  is applied to the gate line GL n+1  which is electrically connected to the selected memory cells  104   a . Herein the voltage difference between the voltage V 16  and the voltage V 17  is not 0, and currents C 5  which pass through the selected memory cells  104   a  are generated. The voltage V 18  is higher than one of the voltage V 16  and the voltage V 17 . When the voltage V 10  is higher than the voltage V 11  in  FIG. 3A , the voltage V 16  is lower than the voltage V 16  in  FIG. 3B . When the voltage V 10  is lower than the voltage V 11  in  FIG. 3A , the voltage V 16  is higher than the voltage V 17  in  FIG. 3B . 
     In the present embodiment, as exemplarily illustrated, the voltage V 16  is 0V, the voltage V 17  is 1.2V, and the voltage V 18  is 0.7V. At this time, with the voltage difference of 1.2 V between the voltage V 16  and the voltage V 17 , the TRIACs  102  which are connected to the selected memory cells  140   a  may be in on-state, thus the currents C 5  may pass from the bit line BL n+1 , through the selected memory cells  140   a  and the TRIACs  102 , and to the source lines SL n , SL n+2 , and the erase operation is performed on the selected memory cells  140   a . Therefore, if the selected memory cells  104   a  are STT-MRAM cells, the magnetoresistance of the selected memory cells  104   a  may be changed due to the currents C 5  which pass through the selected memory cells  104   a , so as to erase the selected memory cells  104   a , and the “0” data is stored in the selected memory cells  104   a.    
     Performing an erase operation on the memory structure  10  further includes the following steps. The voltage V 19  is applied to the source line SL n+1  which is electrically connected to the non-selected memory cells  104   b . The voltage V 20  is applied to the bit lines BL n , BL n+2  which are electrically connected to the non-selected memory cells  104   b . The voltage V 21  is applied to the gate lines GL n , GL n+2  which are electrically connected to the non-selected memory cells  104   b . Herein the voltage V 18  is lower than the voltage V 21 , the voltage difference between the voltage V 19  and the voltage  20  is generally smaller than the voltage difference between the voltage V 16  and the voltage V 17 , thus the TRIACs  102  connected to the non-selected memory cells  104   b  may be in off-state. 
     In the present embodiment, as exemplarily illustrated, the voltage V 19  is 1.2V, the voltage V 20  is 0.6V, and the voltage V 21  is 0.9V. As for the non-selected memory cells  104   b ,  104   c , though there is a voltage difference of 0.6V between the voltage V 19  and the voltage V 20  and between the voltage V 16  and the voltage V 20 , the voltage V 21  (e.g., 0.9V) applied to the gate lines GL n , GL n+2  is higher than the voltage V 18  (e.g., 0.7V) applied to the gate line GL n+1 , and the voltage difference (e.g., 0.6V) between the voltage V 19  and the voltage V 20  and between the voltage V 16  and the voltage V 20  is smaller than the voltage difference (e.g., 1.2V) between the voltage V 16  and the voltage V 17 , due to the currents which pass through the TRIACs  102  connected to the non-selected memory cells  104   b ,  104   c  being extremely tiny, so that the TRIACs  102  connected to the non-selected memory cells  104   b ,  104   c  are in off-state. Therefore, when erase operation is performed on the selected memory cells  104   a , disturbance does not cause to the non-selected memory cells  104   b ,  104   c  and write or erase operation is not performed. 
     In the present embodiment, as for the non-selected memory cells  104   d , the voltage difference (e.g., 0V) between the voltage V 19  and the voltage V 17  is smaller than the voltage difference (e.g., 1.2V) between the voltage V 16  and the voltage V 17 , so that the TRIACs  102  connected to the non-selected memory cells  104   d  are in off-state. In the present embodiment, since the voltage values of the voltage V 19  and the voltage V 17  are equal, the voltage difference between the voltage V 19  and the voltage V 17  is 0V. Thus, no current passes through the TRIACs  102  connected to the non-selected memory cells  104   c , namely, the TRIACs  102  connected to the non-selected memory cells  104   d  are in off-state. Therefore, when erase operation is performed on the selected memory cells  104   a , disturbance does not cause to the non-selected memory cells  104   d  and write or erase operation is not performed. 
     Referring to  FIG. 3C , performing the read operation on the memory cells  104   a  of the memory structure  10  includes the following steps. The voltage V 22  is applied to the source lines SL n , SL n+2  which are electrically connected to the selected memory cells  104   a . The voltage V 23  is applied to the bit line BL n+1  which is electrically connected to the selected memory cells  104   a . The voltage V 24  is applied to the gate line GL n+1  which is electrically connected to the selected memory cells  104   a . Herein the voltage difference between the voltage V 22  and the voltage V 23  is not 0, and currents C 6  which pass through the selected memory cells  104   a  are generated. The voltage V 22  in  FIG. 3C  is higher than one of the voltage V 10  and the voltage V 11  in  FIG. 3A  and lower than the other one of the voltage V 10  and the voltage V 11 . The voltage V 24  is higher than one of the voltage V 22  and the voltage V 23  and generally lower than the other one of the voltage V 22  and the voltage V 23 . 
     In the present embodiment, as exemplarily illustrated, the voltage V 22  is 1V, the voltage V 23  is 0V, and the voltage V 24  is 0.5V. At this time, with the voltage difference of 1V between the voltage V 22  and the voltage V 23 , the TRIACs  102  which are connected to the selected memory cells  140   a  may be in on-state, thus the currents C 6  may pass from the source lines SL n , SL n+2 , through the TRIACs  102  and the selected memory cells  140   a , and to the bit line BL n+1 . Thus, through the currents C 6  which pass through the selected memory cells  104   a , the data stored in the selected memory cells  104   a  may be read. 
     In addition, performing a read operation on the memory structure  10  further includes the following steps. The voltage V 25  is applied to the source line SL n+1  which is electrically connected to the non-selected memory cells  104   b . The voltage V 26  is applied to the bit lines BL n , BL n+2  which are electrically connected to the non-selected memory cells  104   b . The voltage V 27  is applied to the gate lines GL n  GL n+2  which are electrically connected to the non-selected memory cells  104   b . Herein the voltage V 24  is higher than the voltage V 27 . The voltage difference between the voltage V 25  and the voltage V 26  is generally lower than the voltage difference between the voltage V 22  and the voltage V 23 . 
     In the present embodiment, as exemplarily illustrated, the voltage V 25  is 0V, the voltage V 26  is 0.6V, and the voltage V 27  is 0.3V. As for the non-selected memory cells  104   b ,  104   c , though there is a voltage difference of 0.6V between the voltage V 25  and the voltage V 26  and between the voltage V 22  and the voltage V 26 , the voltage V 27  (e.g., 0.3V) applied to the gate lines GL n  GL n+2  is lower than the voltage V 24  (e.g., 0.5V) applied to the gate line GL n+1 , and the voltage difference (e.g., 0.6V) between the voltage V 25  and the voltage V 26  and between the voltage V 22  and the voltage V 26  is smaller than the voltage difference (e.g., 1V) between the voltage V 22  and the voltage V 23 , due to the currents which pass through the TRIACs  102  connected to the non-selected memory cells  104   b ,  104   c  being extremely tiny, so that the TRIACs  102  connected to the non-selected memory cells  104   b ,  104   c  are in off-state. Therefore, when read operation is performed on the selected memory cells  104   a , disturbance does not cause to the non-selected memory cells  104   b ,  104   c  and write or erase operation is not performed, and the wrong reading does not cause to the selected memory cells  104   a.    
     In the present embodiment, as for the non-selected memory cells  104   d , the voltage difference (e.g., 0V) between the voltage V 25  and the voltage V 23  is smaller than the voltage difference (e.g., 1V) between the voltage V 22  and the voltage V 23 , so that the TRIACs  102  connected to the non-selected memory cells  104   d  are in off-state. In the present embodiment, since the voltage values of the voltage V 25  and the voltage V 23  are equal, the voltage difference between the voltage V 25  and the voltage V 23  is 0V. Thus, no current passes through the TRIACs  102  connected to the non-selected memory cells  104   c , namely, the TRIACs  102  connected to the non-selected memory cells  104   d  are in off-state. Therefore, when read operation is performed on the selected memory cells  104   a , disturbance does not cause to the non-selected memory cells  104   d  and write or erase operation is not performed, and the wrong reading does not cause to the selected memory cells  104   a.    
     According to the abovementioned embodiment, in the operation method of the memory structure of the abovementioned embodiment, the memory structure  10  uses the TRIAC  102  as a switch, thus the memory structure  10  has superior electrical characteristic, such as generating leakage current may be suppressed. In addition, in the operation method of the memory structure of the abovementioned embodiment, operation may be performed on the memory structure  10  by using the TRIAC  102 . Through the operation method of the memory structure of the abovementioned embodiment, during performing operation on the selected memory cells  104   a , the memory structure has superior electrical characteristic. For example, when operation is performed on the selected memory cells  104   a , through the TRIACs  102 , disturbance causing to the non-selected memory cells  104   b ,  104   c ,  104   d  may be effectively avoided, write or erase operation is not performed, and the wrong reading does not cause to the selected memory cells  104   a.    
     Although the disclosure has been described with reference to the above embodiments, it will be apparent to one of ordinary skill in the art that modifications to the described embodiments may be made without departing from the spirit of the disclosure. Accordingly, the scope of the disclosure will be defined by the attached claims and not by the above detailed descriptions.