Semiconductor device with polycrystalline silicon emitter conductive layer
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorsYoshiyuki Ishigaki, Hiroki Honda, Kimiharu Uga, Masahiro Ishida
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Abstract
An n.sup.+ buried layer is formed on a surface of p.sup.- semiconductor substrate. An n.sup.- epitaxial growth layer and an n.sup.+ diffusion layer are formed on a surface of n.sup.+ buried layer. A p.sup.- base region and p.sup.+ external base region adjoining to each other are formed on a surface of n.sup.- epitaxial growth layer. An an n.sup.+ emitter region is formed at a surface of p.sup.- base region. An emitter electrode is formed adjacently to n.sup.+ emitter region. The emitter electrode is made of polycrystalline silicon doped with phosphorus at a concentration from 1.times.10.sup.20 cm.sup.-3 to 6.times.10.sup.20 cm.sup.-3.
Claims5
A semiconductor device comprising:
- a semiconductor substrate having a main surface;
- a collector impurity region of a first conductivity type formed at the main surface of said semiconductor substrate;
- a base impurity region of a second conductivity type formed at the main surface of said semiconductor substrate within said collector impurity region;
- an emitter impurity region of the first conductivity type formed at the main surface of said semiconductor substrate within said base impurity region;
- and
- a conductive layer adjoining to said emitter impurity region,
- said conductive layer having a polycrystalline silicon layer substantially uniformly doped with phosphorus at a concentration of at least 1.times.10.sup.20 cm.sup.-3.
Dependencies are inferred from the claim text.