SILICON JUNCTION FIELD-EFFECT TRANSISTORS AT 4.2K

The results of investigations of Polish silicon junction field effect transistors (JFETs) of the BF 245 type at liquid helium temperature are reported. The BF 245B and the BF 245C worked satisfactorily at 4.2 K but the BF 245A transistors were weakly or not controllable in liquid helium. The following changes were observed for BF 245B and 245C transistors: the transconductance is about twice as large at 4.2 K as at 300 K, the absolute value of the pinch-off voltage is about twice as small at 4.2 K and the noise voltage is ten times smaller in liquid helium.