A GaAs MESFET with a partially depleted p layer for SRAMapplications

A GaAs MESFET with a partially depleted p layer that has a specific application to SRAMs has been developed. The short-channel effect is well suppressed for gate lengths down to 0.5 μm by a rather dense p layer buried under the channel. Its acceptor ion dose is as high as 2×10¹² cm^-2, which corresponds to a partially depleted condition. As for applications for SRAMs, it is possible to attain fully functional 7-ns 4-kb SRAMs that are operative at 75°C by using the FET with a 1-μm gate. A chip yield of 22% has been achieved in a 3-in wafer