RTD/HFET low standby power SRAM gain cell

A 50-nW standby power compound semiconductor tunneling-based static random access memory SRAM (TSRAM) cell is demonstrated by combining ultralow current-density resonant-tunneling diodes (RTD's) and heterostructure field-effect transistors (HFET's) in one integrated process on an InP substrate. This power represents over two orders of magnitude improvement over previous III-V static memory cells. By increasing the number of vertically integrated RTD's we obtain a 100 nW tri-state memory cell. The cell concept applies to any material system in which low current-density negative differential resistance devices are available.