A first conductive structure forms gate electrodes of a first transistor of a first transistor type and a first transistor of a second transistor type. A second conductive structure forms a gate electrode of a second transistor of the first transistor type. A third conductive structure forms a gate electrode of a second transistor of the second transistor type. A fourth conductive structure forms a gate electrode of a third transistor of the first transistor type. A fifth conductive structure forms a gate electrode of a third transistor of the second transistor type. A sixth conductive structure forms gate electrodes of a fourth transistor of the first transistor type and a fourth transistor of the second transistor type. The second and third transistors of the first transistor type and the second and third transistors of the second transistor type are electrically connected to form a cross-coupled transistor configuration.

Memory arrays of vertical thyristor memory cells with SiGe base layers are described. The composition of the SiGe can be constant or varied depending upon the desired characteristics of the memory cells. The memory cells allow a compact structure with desirable low voltage operations.

A method of forming a complementary lateral bipolar SRAM device. The device includes: a first set and second set of lateral bipolar transistors forming a respective first inverter device and second inverter device, the first and second inverter devices being cross-coupled for storing a logic state. In each said first and second set, a first bipolar transistor is an PNP type bipolar transistor, and a second bipolar transistor is an NPN type bipolar transistor, each said NPN type bipolar transistor having a base terminal, a first emitter terminal, a second emitter terminal, and a collector terminal. Emitter terminals of the PNP type transistors of each first and second inverter devices are electrically coupled together and receive a first applied wordline voltage. The first emitter terminals of each said NPN transistors of said first inverter and second inverter devices are electrically coupled together and receive a second applied voltage. The second emitter terminal of one NPN bipolar transistor of said first inverter is electrically coupled to a first bit line conductor, and the second emitter terminal of the NPN bipolar transistor of said second inverter device is electrically coupled to a second bit line.

Isolation between vertical thyristor memory cells in an array is improved with isolation regions between the vertical thyristor memory cells. The isolation regions are formed by electrically isolating cores surrounded by insulating material, such as silicon dioxide, in trenches between the memory cells. The electrically isolating cores may be tubes of air or conducting rods. Methods of constructing the isolation regions in a processes for manufacturing vertical thyristor memory cell arrays are also disclosed.

Methods and systems for reducing electrical disturb effects between thyristor memory cells in a memory array are provided. Electrical disturb effects between cells are reduced by using a material having a reduced minority carrier lifetime as a cathode line that is embedded within the array. Disturb effects are also reduced by forming a potential well within a cathode line, or a one-sided potential barrier in a cathode line.

A two-transistor memory cell based upon a thyristor for an SRAM integrated circuit is described together with a process for fabricating it. The memory cell can be implemented in different combinations of MOS and bipolar select transistors, or without select transistors, with thyristors in a semiconductor substrate with shallow trench isolation. Standard CMOS process technology can be used to manufacture the SRAM.

A first conductive structure forms gate electrodes of a first transistor of a first transistor type and a first transistor of a second transistor type. A second conductive structure forms a gate electrode of a second transistor of the first transistor type. A third conductive structure forms a gate electrode of a second transistor of the second transistor type. A fourth conductive structure forms a gate electrode of a third transistor of the first transistor type. A fifth conductive structure forms a gate electrode of a third transistor of the second transistor type. A sixth conductive structure forms gate electrodes of a fourth transistor of the first transistor type and a fourth transistor of the second transistor type. The second and third transistors of the first transistor type and the second and third transistors of the second transistor type are electrically connected to form a cross-coupled transistor configuration.

Methods and systems for reducing electrical disturb effects between thyristor memory cells in a memory array are provided. Electrical disturb effects between cells are reduced by using a material having a reduced minority carrier lifetime as a cathode line that is embedded within the array. Disturb effects are also reduced by forming a potential well within a cathode line, or a one-sided potential barrier in a cathode line.

A two-transistor memory cell based upon a thyristor for an SRAM integrated circuit is described together with a process for fabricating it. The memory cell can be implemented in different combinations of MOS and bipolar select transistors, or without select transistors, with thyristors in a semiconductor substrate with shallow trench isolation. Standard CMOS process technology can be used to manufacture the SRAM.

A method of forming a complementary lateral bipolar SRAM device. The device includes: a first set and second set of lateral bipolar transistors forming a respective first inverter device and second inverter device, the first and second inverter devices being cross-coupled for storing a logic state. In each said first and second set, a first bipolar transistor is an PNP type bipolar transistor, and a second bipolar transistor is an NPN type bipolar transistor, each said NPN type bipolar transistor having a base terminal, a first emitter terminal, a second emitter terminal, and a collector terminal. Emitter terminals of the PNP type transistors of each first and second inverter devices are electrically coupled together and receive a first applied wordline voltage. The first emitter terminals of each said NPN transistors of said first inverter and second inverter devices are electrically coupled together and receive a second applied voltage. The second emitter terminal of one NPN bipolar transistor of said first inverter is electrically coupled to a first bit line conductor, and the second emitter terminal of the NPN bipolar transistor of said second inverter device is electrically coupled to a second bit line.