A correlation has been sought between the microwave performance of indium phosphide transferred electron devices and the metallurgical state of the silver metal-indium phosphide interface that forms the cathode contact in these devices. Both microwave performance and the current-voltage characteristic have been found to depend intimately upon the degree to which a grain structure has developed in the indium phosphide, close to the metal-semiconductor interface. The grain structure appears to act as sites for an alloying reaction involving the silver and the indium phosphide.
Two zone cathode InP t.e.o.s. with plated heat sinks are reported that give peak powers up to 21 W, mean powers up to 1.5 W, and are capable of operation at pulse widths of 50 µs.
Report on International symposium on GaAs and related compounds, 24-26 September 1974 at Deauville, France.
A 2-zone cathode comprising a thin n+ region under a high-resistance contact improves the efficiency on transferred-electron oscillators. InP devices have shown high efficiency over a temperature range of -50 to +150°C.
Efficiencies of up to 21% at 11.0 GHz and 18.5% at 15.2 GHz have been obtained with InP transferred-electron oscillators with evaporated and alloyed cathode contacts made of oxidised Ag-Ga alloy.
