Interuniversitair Microelektronica Centrum (imec)

Moustafa Y Ghannam

Johan F Nijs

Robert Mertens

A bipolar hetero-junction transistor has an emitter formed which consists of doped and hydrogenated semiconductor material which is at least partly in amorphous form. A high current gain (.beta.) is obtained due to the wide bandgap in the emitter material. Preferably, the layer forming the emitter consists of microcrystalline silicon which is doped and hydrogenated. This yields a small base resistance which is preferable for high frequency purposes. The amorphous bipolar hetero-junction transistor can be produced by a CVD-technique, by using a plasma or by photodissociation. The transistor having a microcrystalline emitter layer can be produced by one of the above methods or by heating an amorphous emitter layer.

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Leuven-Heverlee, Belgium

Moustafa Y Ghannam