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US 7,256,472 B2Granted
Bipolar transistor
AssigneeInfineon Technologies AG
InventorsJosef Bock, Thomas Meister, Andriy Romanyuk, Herbert Schäfer
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Abstract
A bipolar transistor and method of making a bipolar transistor is disclosed. In one embodiment, the bipolar transistor includes a polysilicon layer into which impurity atoms are inserted, thereby reducing the layer resistance.
Claims11
A bipolar transistor comprising:
- an emitter area which can be contacted electrically via an emitter electrode;
- a base area which can be contacted electrically via a base electrode;
- a collector area which can be contacted electrically via a collector electrode;
- and
- wherein at least one electrode of the emitter electrode, base electrode and collector electrode is a polysilicon layer, into which doping is inserted and impurity atoms are inserted, wherein the inserting of the impurity atoms causes a high density of vacancies in the polysilicon layer, the density in the range of about 1019 to 1021 cm−3, wherein the impurity atoms are C, P or Ar atoms and wherein the combination of the inserted doping and inserted impurity atoms is such that the electrode resistance is reduced.
2 more elements
A bipolar transistor comprising:
- an emitter area which can be contacted electrically via an emitter electrode;
- a base area which can be contacted electrically via a base electrode;
- a collector area which can be contacted electrically via a collector electrode;
- and
- wherein at least one electrode of the emitter electrode, base electrode and collector electrode is a polysilicon layer doped with boron atoms, into which impurity atoms, which cause a high density of vacancies in the polysilicon layer, are inserted, wherein the impurity atoms are C, P or Ar atoms;
- wherein the density of the impurity atoms in the polysilicon layer is in the range of about 1019 to 1021 cm−3;
- and
- wherein the concentration of the boron atoms is greater than 5×1020 cm−3.
5 more elements
A bipolar transistor comprising:
- an emitter area which can be contacted electrically via an emitter electrode;
- a base area which can be contacted electrically via a base electrode;
- a collector area which can be contacted electrically via a collector electrode;
- wherein a polysilicon layer is used as the base electrode;
- wherein the extrinsic base resistance of the base electrode is reduced by inserting impurity C atoms into the polysilicon layer, thereby causes a high density of vacancies in the polysilicon layer;
- and
- wherein doping is inserted in the polysilicon layer.
4 more elements
Dependencies are inferred from the claim text.