Method for forming polycrystalline thin film bipolar transistors
First Claim
1. A method of forming a bipolar transistor comprising the steps of:
- depositing a layer of amorphous semiconductor material comprising silicon, germanium, or silicon-germanium above a substrate;
depositing a metal in contact with the amorphous semiconductor material;
forming a crystallization template by annealing to react the metal with the amorphous semiconductor material, wherein the crystallization template layer comprises metal silicide, metal germanide or metal silicide-germanide; and
crystallizing the layer of amorphous semiconductor material using the crystallization template, wherein the bipolar transistor comprises a base region, a collector region and an emitter region formed in the crystallized semiconductor material; and
doping the emitter and collector regions with a p-type dopant to form a p-n-p bipolar transistor.
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Abstract
A method is described for forming a semiconductor device comprising a bipolar transistor having a base region, an emitter region and a collector region, wherein the base region comprises polycrystalline semiconductor material formed by crystallizing silicon, germanium or silicon germanium in contact with a silicide, germanide or silicide germanide. The emitter region and collector region also may be formed from polycrystalline semiconductor material formed by crystallizing silicon, germanium or silicon germanium in contact with a silicide, germanide or silicide germanide forming metal. The polycrystalline semiconductor material is preferably silicided polysilicon, which is formed in contact with C49phase titanium silicide.
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Citations
17 Claims
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1. A method of forming a bipolar transistor comprising the steps of:
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depositing a layer of amorphous semiconductor material comprising silicon, germanium, or silicon-germanium above a substrate; depositing a metal in contact with the amorphous semiconductor material; forming a crystallization template by annealing to react the metal with the amorphous semiconductor material, wherein the crystallization template layer comprises metal silicide, metal germanide or metal silicide-germanide; and crystallizing the layer of amorphous semiconductor material using the crystallization template, wherein the bipolar transistor comprises a base region, a collector region and an emitter region formed in the crystallized semiconductor material; and doping the emitter and collector regions with a p-type dopant to form a p-n-p bipolar transistor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for making a thin film bipolar transistor comprising the steps of:
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depositing a layer of amorphous silicon above a substrate; doping a first portion and a second portion of the amorphous silicon layer with a p-type or n-type dopant; depositing a layer of silicide-forming metal adjacent to the amorphous silicon layer; and thermally annealing to react the metal and the amorphous silicon layer to form a metal silicide and to crystallize the amorphous silicon layer to polysilicon, wherein the bipolar transistor has a collector region and an emitter region corresponding to the p-type or n-type doped first and second portions of the polysilicon and a base region formed in the polysilicon. - View Dependent Claims (15, 16, 17)
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Specification