US-12628583-B2 - Method for manufacturing semiconductor device

US12628583B2US 12628583 B2US12628583 B2US 12628583B2US-12628583-B2

Abstract

A method for manufacturing a semiconductor device according to an embodiment includes forming a first mask material having a first opening on a surface of a silicon carbide layer, performing first ion implantation of forming a first carbon region by implanting carbon (C) into the silicon carbide layer using the first mask material as a mask, forming, on the surface of the silicon carbide layer, a second mask material in which both end portions in a first direction parallel to the surface have second openings disposed inside both end portions in the first direction of the first carbon region, performing second ion implantation of forming a first impurity region by implanting a first impurity into the silicon carbide layer using the second mask material as a mask, and performing heat treatment at 1600° C. or higher.

Inventors

Tatsuo Shimizu

Assignees

KABUSHIKI KAISHA TOSHIBA

Dates

Publication Date: 20260512
Application Date: 20220902
Priority Date: 20220322

Claims (13)

1 . A method for manufacturing a semiconductor device, comprising: forming a first mask material having a first opening on a surface of a silicon carbide layer; performing first ion implantation of forming a first carbon region by implanting carbon (C) into the silicon carbide layer using the first mask material as a mask; forming a second mask material having a second opening on the surface of the silicon carbide layer, both end portions of the second opening disposed inside of both end portions of the first carbon region in a first direction parallel to the surface; performing second ion implantation of forming a first impurity region by implanting aluminum (Al) into the silicon carbide layer using the second mask material as a mask; and performing heat treatment at 1600° C. or higher, wherein a maximum concentration of the carbon implanted by the first ion implantation in the silicon carbide layer is higher than a maximum concentration of the aluminum (Al) implanted by the second ion implantation in the silicon carbide layer.
2 . The method for manufacturing a semiconductor device according to claim 1 , wherein a depth of the first carbon region is deeper than a depth of the first impurity region.
3 . The method for manufacturing a semiconductor device according to claim 1 , wherein the first ion implantation is performed at a temperature of 1000° C. or higher.
4 . The method for manufacturing a semiconductor device according to claim 1 , wherein the second ion implantation is performed at a temperature of 1000° C. or higher.
5 . The method for manufacturing a semiconductor device according to claim 1 , wherein a dose amount of the carbon implanted by the first ion implantation is 10 times or more a dose amount of the aluminum (Al) implanted by the second ion implantation.
6 . The method for manufacturing a semiconductor device according to claim 1 , wherein a concentration of a surface of the silicon carbide layer of the carbon implanted by the first ion implantation is 1×10 15 cm −3 or more.
7 . The method for manufacturing a semiconductor device according to claim 1 , wherein a temperature of the heat treatment is 1850° C. or higher.
8 . The method for manufacturing a semiconductor device according to claim 1 , wherein the second mask material is formed by forming a first sidewall material on a sidewall of the first opening.
9 . A method for manufacturing a semiconductor device, comprising: forming a first mask material having a first opening on a surface of a silicon carbide layer; performing first ion implantation of forming a first carbon region by implanting carbon (C) into the silicon carbide layer using the first mask material as a mask; forming a second mask material having a second opening on the surface of the silicon carbide layer, both end portions of the second opening disposed inside of both end portions of the first carbon region in a first direction parallel to the surface; performing second ion implantation of forming a first impurity region by implanting a first impurity into the silicon carbide layer using the second mask material as a mask; performing heat treatment at 1600° C. or higher; and performing third ion implantation of implanting carbon into the silicon carbide layer using the second mask material as a mask before the performing the second ion implantation.
10 . A method for manufacturing a semiconductor device, comprising: forming a first mask material having a first opening on a surface of a silicon carbide layer; performing first ion implantation of forming a first carbon region by implanting carbon (C) into the silicon carbide layer using the first mask material as a mask; forming a second mask material having a second opening on the surface of the silicon carbide layer, both end portions of the second opening disposed inside of both end portions of the first carbon region in a first direction parallel to the surface; performing second ion implantation of forming a first impurity region by implanting a first impurity into the silicon carbide layer using the second mask material as a mask; and performing heat treatment at 1600° C. or higher, wherein the first impurity is nitrogen (N), or phosphorus (P), and a concentration of the carbon implanted by the first ion implantation is higher than a concentration of the first impurity implanted by the second ion implantation at any depth in the silicon carbide layer.
11 . The method for manufacturing a semiconductor device according to claim 8 , further comprising: forming a third mask material having a third opening by forming a second sidewall material on a sidewall of the second opening after the performing the second ion implantation, and forming a trench in the silicon carbide layer using the third mask material as a mask.
12 . The method for manufacturing a semiconductor device according to claim 11 , wherein the first impurity is nitrogen (N) or phosphorus (P).
13 . The method for manufacturing a semiconductor device according to claim 8 , further comprising: removing the second mask material after the performing the second ion implantation; forming a first silicon carbide film on the silicon carbide layer by an epitaxial growth method; forming a third mask material having a third opening on the first silicon carbide film; performing third ion implantation of forming a second carbon region by implanting carbon (C) into the first silicon carbide film using the third mask material as a mask; forming a fourth mask material having a fourth opening by forming a second sidewall material on a sidewall of the third opening after the performing the third ion implantation; performing fourth ion implantation of forming a second impurity region in contact with the first impurity region by implanting aluminum (Al) into the first silicon carbide film using the fourth mask material as a mask; and forming a second silicon carbide film on the silicon carbide layer using an epitaxial growth method.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2022-045395, filed on Mar. 22, 2022, and Japanese Patent Application No. 2022-107884, filed on Jul. 4, 2022, the entire contents of which are incorporated herein by reference. FIELD Embodiments described herein relate generally to a method for manufacturing a semiconductor device. BACKGROUND Silicon carbide (SiC) is expected as a material for next-generation semiconductor devices. As compared with silicon (Si), silicon carbide has excellent physical properties such as a band gap of about 3 times, a breakdown field strength of about 10 times, and a thermal conductivity of about 3 times. By utilizing this characteristic, a semiconductor device capable of operating at a low loss and a high temperature can be realized. From the viewpoint of realizing scaling-down of a semiconductor device using silicon carbide, it is desirable to suppress diffusion of impurities ion-implanted into silicon carbide due to heat treatment. The heat treatment is, for example, high-temperature ion implantation of impurities or activation annealing of impurities. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view of a semiconductor device manufactured by a method for manufacturing a semiconductor device according to a first embodiment; FIG. 2 is an explanatory diagram of the method for manufacturing a semiconductor device according to the first embodiment; FIG. 3 is an explanatory diagram of the method for manufacturing a semiconductor device according to the first embodiment; FIG. 4 is an explanatory diagram of the method for manufacturing a semiconductor device according to the first embodiment; FIG. 5 is an explanatory diagram of the method for manufacturing a semiconductor device according to the first embodiment; FIG. 6 is an explanatory diagram of the method for manufacturing a semiconductor device according to the first embodiment; FIG. 7 is an explanatory diagram of the method for manufacturing a semiconductor device according to the first embodiment; FIG. 8 is an explanatory diagram of the method for manufacturing a semiconductor device according to the first embodiment; FIG. 9 is an explanatory diagram of the method for manufacturing a semiconductor device according to the first embodiment; FIG. 10 is an explanatory diagram of a method for manufacturing a semiconductor device of a comparative example; FIG. 11 is an explanatory diagram of a method for manufacturing a semiconductor device according to a first modification of the first embodiment; FIG. 12 is an explanatory diagram of the method for manufacturing a semiconductor device according to the first modification of the first embodiment; FIG. 13 is an explanatory diagram of a method for manufacturing a semiconductor device according to a second modification of the first embodiment; FIG. 14 is an explanatory diagram of a method for manufacturing a semiconductor device according to a third modification of the first embodiment; FIG. 15 is an explanatory diagram of the method for manufacturing a semiconductor device according to the third modification of the first embodiment; FIG. 16 is an explanatory diagram of the method for manufacturing a semiconductor device according to a third modification of the first embodiment; FIG. 17 is a schematic cross-sectional view of a semiconductor device manufactured by a method for manufacturing a semiconductor device according to a second embodiment; FIG. 18 is an explanatory diagram of the method for manufacturing a semiconductor device according to the second embodiment; FIG. 19 is an explanatory diagram of the method for manufacturing a semiconductor device according to the second embodiment; FIG. 20 is an explanatory diagram of the method for manufacturing a semiconductor device according to the second embodiment; FIG. 21 is an explanatory diagram of the method for manufacturing a semiconductor device according to the second embodiment; FIG. 22 is an explanatory diagram of the method for manufacturing a semiconductor device according to the second embodiment; FIG. 23 is an explanatory diagram of the method for manufacturing a semiconductor device according to the second embodiment; FIG. 24 is an explanatory diagram of the method for manufacturing a semiconductor device according to the second embodiment; FIG. 25 is an explanatory diagram of the method for manufacturing a semiconductor device according to the second embodiment; FIG. 26 is an explanatory diagram of the method for manufacturing a semiconductor device according to the second embodiment; FIG. 27 is an explanatory diagram of the method for manufacturing a semiconductor device according to the second embodiment; FIG. 28 is a schematic cross-sectional view of a semiconductor device manufactured by a method for manufacturing a semiconductor device according to a modification of the second embodiment; FIG. 29 is