A 1.2 ns GaAs 4 K read only memory

The first commercially available GaAs 4 K ROM (read-only memory) has been designed and manufactured using the 3-level metal HMED (high-margin enhancement/depletion) process. The access time of 1.2 ns is obtained with a power dissipation of 1.9 W. It is concluded that extra margin in the circuit design for a wide range of power supply variation and processing window has contributed to good processing yield. The design criteria also allow the target pinch-off voltage to be changed for a particular application need in power/speed combination.<>