High-density static ESFI MOS memory cells

The area of static MOS memory cells is reduced by avoiding crossovers in the flip-flop, and by selecting the cell by a diode. Such cells have been realized in epitaxial silicon films on insulators (ESFI) with complementary transistors, diodes, and high-rated load resistors; the cell areas can be as small as 1500 μm/SUP 2/ (2.4 mil/SUP 2/), and are the smallest areas of static MOS memory cells known so far. The static and dynamic behavior of these cells are discussed, as well as their behavior in a large-scale integrated (LSI) circuit; for this purpose an exploratory memory with 4096 bits and with simple decoding and sensing circuitry has been realized on an area of 3.5×4.2 mm (140×170 mils). Taking into account the measured data, an ESFI MOS memory circuit shows a better performance in speed and power dissipation than dynamic MOS memories, but its principal advantage is the static operation mode.