Injection-coupled memory: A high-density static bipolar memory

The design of a new static bipolar memory comparable with dynamic FET storages in density, but superior in performance and power dissipation is discussed. The concept of direct minority carrier injection is utilized for both the cell current supply and the coupling to the read/write lines. This has led to an extremely high degree of device integration resulting in a cell size of 3.1 mil/SUP 2/ using a standard buried layer process with 5-μ line dimensions and single layer metallization. Investigations on exploratory chips containing small arrays have fully verified the feasibility. The cells have been operated at an extremely small d.c. standby power of below 100 nW. For a 4K b chip of about 160×150 mil/SUP 2/, an access time around 50 ns can be projected from the measurements simulating a 64×64 bit array. An extrapolation of the memory cell layout with oxide isolation and self-aligned N/SUP +/ contacts has resulted in a 1.1-mil/SUP 2/ cell with 5-μ line dimensions.