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Low Temperature Performance Of Field Effect Transistors, Wei Zhu

Theses

The low temperature static characteristics of silicon junction field-effecttransistors (JFETs) have been investigated and analysed. The followingchanges were observed after cooling down the transistors: pinch-offvoltage and transconductance increases; and drain current is changedas a function of the drain-source voltage. It was found that there wasan increase in the amplifying properties and a reduction in noise voltageof cooled transistors. In addition, the temperature and voltage dependenceof leakage current have been studied. Temperatures below 77K are ofinterest in evaluating effects of impurity freezeout and temperatureabove 77K are important since actual device temperature will be aboutthe ambient. Operation of FET circuits at liquid …