US 6,387,769 B2 · Method of producing a schottky varicap

Abstract

A method of producing a Schottky varicap (25) including: (a) providing an epitaxial layer (12) on a semiconductor substrate (1); (b) providing an insulating layer including an oxide layer and a nitride layer on a predetermined area of the surface of the epitaxial layer (12); (c) depositing a polysilicon layer (6); (d) applying a first high temperature step to diffuse a guard ring (10) around the first predetermined area; (e) removing a predetermined portion of the polysilicon layer (6) to expose the first silicon nitride film (5); (f) implanting atoms through at least the first oxide film (4) to provide a predetermined varicap doping profile; (g) applying a second high temperature step to anneal and activate the varicap doping profile; (h) removing the first oxide film (4) to provide an exposed area; (i) providing a Schottky electrode (17) on the exposed area.

Claims14

Dependent claims

A method of producing a Schottky varicap (25) using the following steps:

(a) providing an epitaxial layer (12) on a semiconductor substrate (1), the epitaxial layer (12) having an upper surface and being of a first conductivity type;
(b) providing an insulating layer, and patterning the insulating layer to provide an insulating film on a predetermined area of said surface of said epitaxial layer (12), said insulating film comprising an oxide film (4) contacting the epitaxial film (12) on said predetermined area and a silicon nitride film (5) above the oxide film (4);
(c) depositing a polysilicon layer (6) of a second conductivity type;
(d) applying a first high temperature step to diffuse a guard ring (10) of said second conductivity type into the epitaxial layer (12) around said first predetermined area;
(e) removing a predetermined portion of said polysilicon layer (6) to expose said first silicon nitride film (5);
(f) implanting atoms through at least said first oxide film (4) to provide said epitaxial layer with a predetermined varicap doping profile;
(g) applying a second high temperature step to anneal and activate said varicap doping profile;
(h) removing said first oxide film (4) to provide an exposed area of said upper surface of said epitaxial layer (12) with the predetermined varicap doping profile;
(i) providing a Schottky electrode (17) on said exposed area.

6 more elements

A method of producing a Schottky varicap (25) simultaneously with a transistor (27) on a single chip using the following steps:

(a) providing an epitaxial layer (12) on a semiconductor substrate (1), the epitaxial layer (12) having an upper surface and being of a first conductivity type;
(b) providing an insulating film on a first predetermined area of said surface of said epitaxial layer (12), said insulating film comprising a first oxide film (4) contacting the epitaxial layer (12) and a first silicon nitride film (5) above the first oxide film (4);
(c) depositing a polysilicon layer (6) of a second conductivity type;
(d) providing an opening (A) in said polysilicon layer (6) at a second predetermined area of said surface of said epitaxial layer (12);
(e) applying a first high temperature step to diffuse a guard ring (10) of said second conductivity type into the epitaxial layer (12) around said first predetermined area and to diffuse a base contact region (14) adjacent to said second predetermined area;
(f) providing a base diffusion region (15) of a second conductivity type in said epitaxial layer (12) below said opening (A);
(g) providing an emitter contact (8) in said opening (A), which emitter contact is electrically insulated from said polysilicon layer (6);
(h) removing a predetermined portion of said polysilicon layer (6) to expose said first silicon nitride film (5);
(i) implanting atoms through at least said first oxide film (4) to provide said epitaxial layer with a predetermined varicap doping profile;
(j) applying a second high temperature step to diffuse an emitter region (18) into said epitaxial layer (12), and to anneal and activate said varicap doping profile;
(k) removing said first oxide film (4) to provide an exposed area of said upper surface of said epitaxial layer (12) with the predetermined varicap doping profile;
(l) providing a Schottky electrode (17) on said exposed area.

9 more elements

A method of producing a Schottky varicap (25) simultaneously with a high density capacitor (26) using the following steps:

(a) providing an epitaxial layer (12) on a semiconductor substrate (1), the epitaxial layer (12) having an upper surface and being of a first conductivity type;
(b) implanting atoms in a second predetermined area of said upper surface to provide said epitaxial layer in said second predetermined area with a high doping concentration;
(c) providing an insulating layer, and patterning the insulating layer to provide a first insulating film on a first predetermined area of said surface of said epitaxial layer (12) and a second insulating film on said second predetermined area of said surface of said epitaxial layer (12), said first insulating film comprising a first oxide film (4) contacting the epitaxial film (12) on said first predetermined area and a first silicon nitride film (5) above the first oxide film (4), said second insulating film comprising a second oxide film (4′) contacting the epitaxial film (12) on said second predetermined area and a second silicon nitride film (5′) above the second oxide film (4′);
(d) depositing a polysilicon layer (6) of a second conductivity type;
(e) applying a first high temperature step to diffuse a guard ring (10) of said second conductivity type into the epitaxial layer (12) around said first predetermined area;
(f) removing a predetermined portion of said polysilicon layer (6) to expose said first silicon nitride film (5);
(g) implanting atoms through at least said first oxide film (4) to provide said epitaxial layer with a predetermined varicap doping profile;
(h) applying a second high temperature step to anneal and activate said varicap doping profile;
(i) removing said first oxide film (4) to provide an exposed area of said upper surface of said epitaxial layer (12) with the predetermined varicap doping profile;
(j) providing a Schottky electrode (17) on said exposed area.

7 more elements

A method of producing a Schottky varicap (25) simultaneously with a transistor (27) and a high density capacitor on a single chip using the following steps:

(a) providing an epitaxial layer (12) on a semiconductor substrate (1), the epitaxial layer (12) having an upper surface and being of a first conductivity type;
(b) implanting atoms in a second predetermined area of said upper surface to provide said epitaxial layer in said second predetermined area with a high doping concentration;
(c) providing an insulating layer, and patterning the insulating layer to provide a first insulating film on a first predetermined area of said surface of said epitaxial layer (12) and a second insulating film on a second predetermined area of said surface of said epitaxial layer (12), said first insulating film comprising a first oxide film (4) contacting the epitaxial film (12) on said first predetermined area and a first silicon nitride film (5) above the first oxide film (4), said second insulating film comprising a second oxide film (4′) contacting the epitaxial film (12) on said second predetermined area and a second silicon nitride film (5′) above the second oxide film (4′);
(d) depositing a polysilicon layer (6) of a second conductivity type;
(e) providing an opening (A) in said polysilicon layer (6) at a third predetermined area of said surface of said epitaxial layer (12);
(f) applying a first high temperature step to diffuse a guard ring (10) of said second conductivity type into the epitaxial layer (12) around said first predetermined area and to diffuse a base contact region (14) adjacent to said third predetermined area;
(g) providing a base diffusion region (15) of a second conductivity type in said epitaxial layer (12) below said opening (A);
(h) providing an emitter contact (8) in said opening (A), which emitter contact is electrically insulated from said polysilicon layer (6);
(i) removing a predetermined portion of said polysilicon layer (6) to expose said first silicon nitride film (5);
(j) implanting atoms through at least said first oxide film (4) to provide said epitaxial layer with a predetermined varicap doping profile;
(k) applying a second high temperature step to diffuse an emitter region (18) into said epitaxial layer (12), and to anneal and activate said varicap doping profile;
(l) removing said first oxide film (4) to provide an exposed area of said upper surface of said epitaxial layer (12) with the predetermined varicap doping profile;
(m) providing a Schottky electrode (17) on said exposed area.

10 more elements

Dependencies are inferred from the claim text.

Method of producing a schottky varicap

Life of this patent

Method of producing a schottky varicap

Life of this patent

Abstract

Claims14