Operation of field-effect transistors at liquid-helium temperature

D.C. operation of silicon m.o.s.t., devices of pchannel enhancement and nchannel depletion types at 4°K is described. The former has transfer and drain characteristics at 4°K which are substantially similar to those at room temperature. The latter has a nonlinear ID/VD characteristic. A large drain `threshold¿ is found in a few devices and is traced to the absence of gate overlap with drain and source contacts.