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US-20260129896-A1 - SEMICONDUCTOR DEVICE

US20260129896A1US 20260129896 A1US20260129896 A1US 20260129896A1US-20260129896-A1

Abstract

According to one embodiment, a semiconductor device includes a semiconductor layer, a first electrode, a second electrode, and a gate electrode. The semiconductor layer contains gallium nitride. The semiconductor layer includes a first region, a second region, a third region, and a fourth region. The third region is located between the first region and the second region in a first direction. The first direction is from the first region toward the second region. The fourth region is located between the second region and the third region. A hydrogen concentration in the fourth region is higher than a hydrogen concentration in the third region. The first electrode is provided on the first region. The second electrode is provided on the second region. The gate electrode is provided on the third region with a first insulating layer interposed.

Inventors

  • Hitoshi Kobayashi
  • Yorito Kakiuchi
  • Akira Yoshioka
  • Tetsuya Ohno
  • Ken Hirose
  • Hideki Sekiguchi

Assignees

  • KABUSHIKI KAISHA TOSHIBA
  • TOSHIBA ELECTRONIC DEVICES & STORAGE CORPORATION

Dates

Publication Date
20260507
Application Date
20251219

Claims (9)

  1. 1 . A semiconductor device comprising: a semiconductor layer containing gallium nitride and including a first region, a second region, a third region located between the first region and the second region in a first direction from the first region toward the second region, and a fourth region located between the second region and the third region, a hydrogen concentration in the fourth region being higher than a hydrogen concentration in the third region; a first electrode provided on the first region; a second electrode provided on the second region; and a gate electrode provided on the third region with a first insulating layer interposed.
  2. 2 . The semiconductor device according to claim 1 , further comprising a field plate electrode provided on the gate electrode and electrically connected to the gate electrode, an end of the field plate electrode in the first direction being located on a side toward the second electrode with respect to the gate electrode, and the field plate electrode being located above the third region.
  3. 3 . The semiconductor device according to claim 1 , wherein the hydrogen concentration in the third region is less than 1.0×10 21 cm −3 , and the hydrogen concentration in the fourth region is not less than 1.0×10 21 cm −3 .
  4. 4 . The semiconductor device according to claim 1 , further comprising a second insulating layer provided on the fourth region and in contact with the fourth region, a hydrogen concentration in the second insulating layer being higher than a hydrogen concentration in the first insulating layer.
  5. 5 . The semiconductor device according to claim 4 , wherein the hydrogen concentration in the first insulating layer is less than 1.0×10 22 cm −3 , and the hydrogen concentration in the second insulating layer is not less than 1.0×10 22 cm −3 .
  6. 6 . The semiconductor device according to claim 1 , wherein the hydrogen concentration in the fourth region is higher than a hydrogen concentration in the first region and is higher than a hydrogen concentration in the second region.
  7. 7 . The semiconductor device according to claim 1 , wherein the semiconductor layer includes a fifth region located between the first region and the third region, and a hydrogen concentration in the fifth region is higher than the hydrogen concentration in the third region.
  8. 8 . The semiconductor device according to claim 1 , wherein the fourth region includes a first portion and a second portion located between the first portion and the second region, and a hydrogen concentration in the second portion is higher than a hydrogen concentration in the first portion.
  9. 9 . The semiconductor device according to claim 1 , wherein the semiconductor layer includes a first layer containing Al x1 Ga 1−x1 N (0≤x1<1), and a second layer provided on the first layer and containing Al x2 Ga 1−x2 N (0<x2<1, x1<x2), the second layer includes the first region, the second region, the third region, and the fourth region, and the hydrogen concentration in the fourth region is higher than a hydrogen concentration in a region of the first layer located directly below the fourth region.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This is a continuation application of International Patent Application PCT/JP 2024/009360, filed on Mar. 11, 2024. The entire contents of which are incorporated herein by reference. FIELD Embodiments described herein relate generally to a semiconductor device. BACKGROUND A semiconductor device using gallium nitride is known. For this semiconductor device, a reduction in on-resistance has been demanded. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view illustrating a semiconductor device according to an embodiment; FIGS. 2A to 2C are cross-sectional views illustrating a method for manufacturing the semiconductor device according to the embodiment; FIGS. 3A and 3B are cross-sectional views illustrating the method for manufacturing the semiconductor device according to the embodiment; FIGS. 4A to 4C are cross-sectional views illustrating the method for manufacturing the semiconductor device according to the embodiment; FIG. 5A is a cross-sectional view illustrating a semiconductor device according to a reference example, and FIG. 5B is a graph illustrating characteristics of the semiconductor device according to the reference example; FIG. 6A is a cross-sectional view illustrating the semiconductor device according to the embodiment, and FIG. 6B is a graph showing characteristics of the semiconductor device according to the embodiment; FIG. 7 is an enlarged cross-sectional view of a part of the semiconductor device according to the embodiment; FIG. 8A is a cross-sectional view illustrating a semiconductor device according to a first modified example of the embodiment, and FIG. 8B is a graph illustrating characteristics of the semiconductor device according to the first modified example of the embodiment; and FIG. 9A is a cross-sectional view illustrating a semiconductor device according to a second modified example of the embodiment, and FIG. 9B is a graph illustrating characteristics of the semiconductor device according to the second modified example of the embodiment. DETAILED DESCRIPTION According to one embodiment, a semiconductor device includes a semiconductor layer, a first electrode, a second electrode, and a gate electrode. The semiconductor layer contains gallium nitride. The semiconductor layer includes a first region, a second region, a third region, and a fourth region. The third region is located between the first region and the second region in a first direction. The first direction is from the first region toward the second region. The fourth region is located between the second region and the third region. A hydrogen concentration in the fourth region is higher than a hydrogen concentration in the third region. The first electrode is provided on the first region. The second electrode is provided on the second region. The gate electrode is provided on the third region with a first insulating layer interposed. Various embodiments will be described hereinafter with reference to the accompanying drawings. The drawings are schematic and conceptual; and the relationships between the thickness and width of portions, the proportions of sizes among portions, etc., are not necessarily the same as the actual values thereof. Further, the dimensions and proportions may be illustrated differently among drawings, even for identical portions. In the specification and drawings, components similar to those described or illustrated in a drawing thereinabove are marked with like reference numerals, and a detailed description is omitted as appropriate. FIG. 1 is a cross-sectional view illustrating a semiconductor device according to an embodiment. As shown in FIG. 1, a semiconductor device 100 according to the embodiment includes a semiconductor substrate 1, a semiconductor layer 10, a source electrode 21 (first electrode), a drain electrode 22 (second electrode), a gate electrode 23, a field plate electrode (FP electrode) 24, an FP electrode 25, an FP electrode 26, a first insulating layer 31, a second insulating layer 32, and a third insulating layer 33. In the description of the embodiment, an XYZ orthogonal coordinate system is used. A direction from the semiconductor substrate 1 toward the semiconductor layer 10 is defined as a Z-direction. Two directions that are perpendicular to the Z-direction and perpendicular to each other are defined as an X-direction (first direction) and a Y-direction. For convenience of explanation, the direction from the semiconductor substrate 1 toward the semiconductor layer 10 is referred to as “upward”, and the opposite direction is referred to as “downward”. These directions are based on a relative positional relationship between the semiconductor substrate 1 and the semiconductor layer 10 and are independent of the direction of gravity. The semiconductor layer 10 is provided on the semiconductor substrate 1. The semiconductor layer 10 contains gallium nitride. Specifically, the semiconductor layer 10 includes a first la