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US 4,937,204 AGranted
Method of making a superlattice heterojunction bipolar device
AssigneeSony Corporation
InventorsAkira Ishibashi, Yoshifumi Mori, Masao Itabashi
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Abstract
A semiconductor apparatus is disclosed, in which the entire or part of an electron active region is formed by a superlattice structure semiconductor layer in which a plurality of different semiconductor layers, less than 8 monolayers, and containing a fraction or a binary compound semiconductor layers are alternately and epitaxially grown and a main current direction is selected to be in the direction perpendicular to the laminae of said superlattice layers.
Claims5
A method of forming a superlattice device comprising the successive steps of:
- (a) epitaxially growing on a semiinsulating substrate an N type GaAs collector layer of low resistivity;
- (b) epitaxially growing an N type, AlGaAs collector layer having a large band-gap;
- (c) epitaxially growing a P doped superlattice structure, constituting a base layer and forming a pn junction with the AlGaAs collector layer by forming n monolayers of a first compound semiconductor followed by m monolayers of a second compound semiconductor followed by n monolayers of the first compound semiconductor, and so on, ending with m monolayers of the second semiconductor, where n and m are less than eight;
- (d) epitaxially growing an N type AlGaAs emitter layer having a large band-gap and which forms an emitter junction of the heterojunction type with the superlattice base layer;
- (e) epitaxially growing an N type GaAs emitter layer;
- (f) epitaxially growing an N type GaAs emitter layer of low resistivity;
- and
- (g) causing electrons to flow perpendicularly through the monolayers.
5 more elements
Dependencies are inferred from the claim text.