Method for making bipolar transistor by self-aligning the emitter to the base contact diffusion

Claim 1

An improved method for making a semiconductor structure, wherein the structure has a bipolar transistor portion with a self-aligned extrinsic base, and a capacitor portion having a pair of polysilicon electrodes separated by a dielectric region, the improvement comprising forming the self-aligned extrinsic base simultaneously with the dielectric region.

Claim 3

A method for making a semiconductor structure on a semiconductive substrate having a field oxide region and a buffer oxide region thereon, the structure having a bipolar transistor portion with a self-aligned extrinsic base and a capacitor portion having a pair of polysilicon electrodes separated by a silicon dioxide-silicon nitride-silicon dioxide dielectric region, said method comprising: a. depositing a first layer of polysilicon on a portion of the field oxide region, forming a first polysilicon electrode; b. oxidizing the first polysilicon electrode; c. depositing a silicon nitride layer over the oxidized polysilicon and the buffer oxide region; d. masking an extrinsic base region over a portion of the buffer oxide region; e. etching the silicon nitride layer to form an opening in the nitride layer above the portion of the buffer oxide region; f. implanting a dopant material through the window to form the extrinsic base; g. oxidizing the nitride layer while simultaneously diffusing the dopant material in said base; and h. depositing a second layer of polysilicon on the oxidized nitride layer, forming the second polysilicon electrode.

Claim 4

A method for making a semiconductor structure on a semiconductive substrate having a field oxide region and a buffer oxide region thereon, the structure having a bipolar transistor portion with a self-aligned extrinsic base and a capacitor portion having a pair of polysilicon electrodes separated by a silicon dioxide-silicon nitride-silicon dioxide dielectric region, said method comprising: a. depositing a first layer of polysilicon on a portion of the field oxide region, forming a first polysilicon electrode; b. oxidizing the first polysilicon electrode; c. depositing a silicon nitride layer over the oxidized polysilicon and the buffer oxide region; d. masking an extrinsic base region over a portion of the buffer oxide region; e. etching the silicon nitride layer to form an opening in the nitride layer above the portion of the buffer oxide region; f. implanting a dopant material through the window to form the extrinsic base; g. oxidizing the nitride layer while simultaneously diffusing the dopant material in said base; and h. depositing a second layer of polysilicon on the oxidized nitride layer, forming the second polysilicon electrode.

Claim 5

A method for making a semiconductor structure, comprising: a. forming a field oxide region and a buffer oxide region on a silicon substrate; b. forming a first capacitor electrode on a portion of the field oxide region; c. forming an insulating dielectric region over the first electrode to isolate the first electrode; d. forming a self-aligned extrinsic base region of a bipolar transistor in a first portion of the silicon substrate simultaneously with the formation of the insulating dielectric region; e. forming a second capacitor electrode over the dielectric region; f. forming an emitter region of said bipolar transistor in a second portion of the silicon substrate; and g. forming a collector region of said bipolar transistor in a third portion of the silicon substrate.

Claim 6

A method for making a semiconductor structure, comprising: a. forming a field oxide region and a buffer oxide region on a silicon substrate; b. forming a first capacitor electrode on a portion of the field oxide region; c. forming an insulating dielectric region over the first electrode to isolate the first electrode; d. forming a self-aligned extrinsic base region of a bipolar transistor in a first portion of the silicon substrate simultaneously with the formation of the insulating dielectric region; e. forming a second capacitor electrode over the dielectric region; f. forming an emitter region of said bipolar transistor in a second portion of the silicon substrate; and g. forming a collector region of said bipolar transistor in a third portion of the silicon substrate.

Claim 10

A method for making a semiconductor structure on a semiconductive substrate having a field oxide region and a buffer oxide region thereon, the structure having a bipolar transistor portion with a self-aligned extrinsic base and a capacitor portion having a pair of polysilicon electrodes separated by a silicon dioxide-silicon nitride-silicon dioxide dielectric region, said method comprising: a. depositing a first layer of polysilicon on a portion of the field oxide region, forming a first polysilicon electrode; b. oxidizing the first polysilicon electrode; c. depositing a silicon nitride layer over the oxidized polysilicon and the buffer oxide region; d. oxidizing the nitride layer; e. masking the structure to form a window over a portion of the buffer oxide region; f. implanting a dopant material through the window to form the base region; g. masking the structure to form simultaneously a dielectric region over the first polysilicon electrode and a region above the portion over the buffer oxide region to expose the substrate to a base contact diffusion region and an emitter region; and h. depositing a second layer of polysilicon on the oxidized nitride layer, forming the second polysilicon electrode.

Claim 11

A method for making a semiconductor structure on a semiconductive substrate having a field oxide region and a buffer oxide region thereon, the structure having a bipolar transistor portion with a self-aligned extrinsic base and a capacitor portion having a pair of polysilicon electrodes separated by a silicon dioxide-silicon nitride-silicon dioxide dielectric region, said method comprising: a. depositing a first layer of polysilicon on a portion of the field oxide region, forming a first polysilicon electrode; b. oxidizing the first polysilicon electrode; c. depositing a silicon nitride layer over the oxidized polysilicon and the buffer oxide region; d. oxidizing the nitride layer; e. masking the structure to form a window over a portion of the buffer oxide region; f. implanting a dopant material through the window to form the base region; g. masking the structure to form simultaneously a dielectric region over the first polysilicon electrode and a region above the portion over the buffer oxide region to expose the substrate to a base contact diffusion region and an emitter region; and h. depositing a second layer of polysilicon on the oxidized nitride layer, forming the second polysilicon electrode.