Patent ID: 6828602
Filing Date: 2004-12-07
Classification: H01L,Y10S

Abstract:
A bipolar transistor, comprising:a first semiconductor layer to be a collector layer formed on a substrate and including an impurity of a first conductive type; a second semiconductor layer to be a base layer formed on said first semiconductor layer and including an impurity of a second conductive type; a third semiconductor layer formed on said second semiconductor layer from a material having a bandgap different from a bandgap of said second semiconductor layer; an insulator film provided on said third semiconductor layer; an opening portion formed through said insulator film to reach said third semiconductor layer; and an emitter connecting electrode made of a conductor material and brought into contact with said third semiconductor layer by filling said opening portion in said insulator film, wherein said third semiconductor layer includes an emitter diffusion layer of the first conductive type positioned below said opening portion, and a peripheral layer located at a side of said emitter diffusion layer, and said peripheral layer includes the impurity of the second conductive type so as to be distributed at a high concentration in an upper part, at a low concentration at the center and at a high concentration in a lower part within the peripheral layer.