# HCl-based halide vapor phase epitaxy and selective-area HCl gas etching of (−112) β-Ga                    <sub>2</sub>                    O                    <sub>3</sub>

https://mdr.nims.go.jp/datasets/ab03d179-9596-4c80-9dfe-2b3f4bc2b02e

## File

- [paper_-112.pdf](https://mdr.nims.go.jp/filesets/20623479-49f1-4406-8bce-2cca2c123c51/download) ([Detail](https://mdr.nims.go.jp/filesets/20623479-49f1-4406-8bce-2cca2c123c51.md))

## Id

ab03d179-9596-4c80-9dfe-2b3f4bc2b02e

## Local identifier



## Visibility

open_to_public

## State

published

## Created at

2026-07-16T00:14:57.106086Z

## Updated at

2026-07-16T01:12:49.922675Z

## Published at

2026-07-16T03:36:07.768010Z

## Doi



## First published url

https://doi.org/10.1080/14686996.2026.2680969

## Date published

2026-12-31

## Recorded date published

2026-12-31

## Resource type

journal_article

## Manuscript type

vor

## Collection



## Title

- title: |-
    HCl-based halide vapor phase epitaxy and selective-area HCl gas etching of (−112) β-Ga
                        <sub>2</sub>
                        O
                        <sub>3</sub>
  title_type: original
  lang: en

## Description

- description: We propose (−112) and crystallographically equivalent (1−1−2), (−1−12),
    and (11−2) planes as fundamental crystal orientations for β-Ga2O3 studies. In
    homoepitaxy, the epilayer exhibited single crystallinity with tilt and twist dispersions
    comparable to those of the substrate and a step-and-terrace surface morphology
    with a root-mean-square roughness of 0.10–0.12 nm. Although slit-like pits whose
    sidewalls were vertically aligned (100) facets appeared on the surface, these
    pits were attributed to SiO2 nanomasks at the interface and are expected to be
    eliminated by improving pre-growth surface treatments or the initial growth process.
    Furthermore, the concentration of Cl impurities in the epilayer was as low as
    1×1015 cm−3, which was significantly lower than 2×1016 cm−3 observed in the simultaneously
    grown (001)-oriented homoepitaxial layer. For HCl gas etching, selective-area
    etching was performed using a SiO2 mask with patterned windows. The etched structures
    clearly reflected the intrinsic crystal anisotropy. Side etching was minimized
    when the windows were aligned along the [02−1] direction due to the formation
    of exceptionally flat and vertical (100) facets, which possess the lowest surface
    energy density. Additionally, the vertical etch rate for the (−112) plane was
    approximately 50 times higher than the side etch rate for the (100) plane, enabling
    precise fabrication of high-aspect-ratio fins and trenches. These results—particularly
    the excellent surface smoothness achieved in homoepitaxy and the high-aspect-ratio
    patterning enabled by HCl-gas etching—demonstrate that the {−112} orientations
    are promising candidates for β-Ga2O3 studies.
  description_type: abstract
  lang: und

## Creator

- name: Takayoshi Oshima
  role: author
  orcid: https://orcid.org/0000-0001-8550-9735
- name: Yuichi Oshima
  role: author
  orcid: https://orcid.org/0000-0001-8293-4891

## Contact agent



## Publisher

organization: Informa UK Limited

## Managing organization



## Keyword

- subject: Ga2O3
  schema: not_defined
- subject: "(−112)"
  schema: not_defined
- subject: HVPE
  schema: not_defined
- subject: HCl gas etching
  schema: not_defined

## Rights

- identifier: https://creativecommons.org/licenses/by/4.0/

## Other identifier(s)



## Data origin



## Embargo



## Journal

- title: Science and Technology of Advanced Materials
  issn: '14686996'
  volume: '27'
  issue: '1'
  article_number: '2680969'

## Conference



## Related item



## Funding

- identifier: JP24K01368
  funder_name: Japan Society for the Promotion of Science
- identifier: JPNP22007
  funder_name: New Energy and Industrial Technology Development Organization (NEDO),
    Ministry of Economy, Trade and Industry (METI), Japan

## Instrument



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## Specimen



## Chemical composition



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## Fileset

- id: 20623479-49f1-4406-8bce-2cca2c123c51
  filename: paper_-112.pdf
  content_type: application/pdf
  size: 8015884
  md5: 8b6467a3eda65128262725f01e4c3eee

## Thumbnail

fileset_id: 20623479-49f1-4406-8bce-2cca2c123c51
filename: paper_-112.pdf