摘要 |
An insulated gate field-effect transistor is fabricated to include an improved insulation layer comprising a film of silicon dioxide covered with a film of silicon nitride. The method of fabrication includes the thermal oxidation of a semiconductor silicon surface in a "reducing" atomsphere. The use of hydrogen as a carrier gas for oxygen provides a thermally grown, pinhole-free oxide film having improved stability under conditions of heat cycling and electrical bias. The process permits a control of oxidation rate by adjusting the oxygen content of the gaseous mixture, rather than by the control of temperature. Best device characteristics are obtained by proceeding immediately with the vapor deposition of silicon nitride on the oxide, as a substantially continuous operation in the same reactor.
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