MANUFACTURE OF HETERO-JUNCTION BIPOLAR TRANSISTOR HAVING CARBON-DOPED BASE LAYER

摘要

PROBLEM TO BE SOLVED: To dope a base layer with carbon which is p-type impurities with a high concentration and to improve a current gain. SOLUTION: Immediately after a buffer layer, a sub-collector layer, a collector layer, a base layer and an emitter layer are formed by vapor phase growth on a substrate whose temperature is kept at 585 deg.C, the substrate temperature is lowered to 495 deg.C as shown in Fig. 1J and 1st and 2nd emitter cap layers are formed by vapor phase growth while the substrate temperature is kept at 495 deg.C. TEGa(triethyl gallium) is used as raw material of Ga for the growth of the 1st emitter cap layer made of GaAs.