Arsenic diffusion in MOVPE-Grown GaAs/Ge epitaxial structures

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Hauptverfasser: Orejuela, V., Garcia-Tabares, E., Rey-Stolle, I., Garcia, I.
Format: Preprint
Veröffentlicht: 2024
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author Orejuela, V.
Garcia-Tabares, E.
Rey-Stolle, I.
Garcia, I.
author_facet Orejuela, V.
Garcia-Tabares, E.
Rey-Stolle, I.
Garcia, I.
contents Germanium is reemerging as a prominent material in the semiconductor field, particularly for electronic applications, photonics, photovoltaics and thermophotovoltaics. Its combination with III-V compound semiconductors through epitaxial growth by metal organic vapor phase epitaxy (MOVPE) is instrumental and thus, the comprehension of the sequential stages in such epitaxial processes is of great importance. During the deposition of GaAs on p-type Ge, the formation of n/p junctions occurs when As diffuses into Ge. It is found that this formation begins in the so-called AsH3 preexposure where Ge substrate is firstly exposed to AsH3. Also important is the fact that both free carrier profiles and As profiles indicate that prolonged AsH3 preexposure times lead to deeper diffusion depths for the same process time. This effect is concomitant with the degradation of the Ge surface morphology, characterized by higher roughness as the AsH3 preexposure duration is extended. Contrary to ion-implanted As in germanium, which shows quadratic dependent diffusivity, our MOVPE investigation using AsH3 indicates a linear relationship, consistent with Takenaka et al.'s MOVPE study using TBAs. Analyzing As profiles alongside simulations, with and without subsequent GaAs epitaxy, suggests the generation of Ge vacancies during the process, contributing to deeper As diffusion.
format Preprint
id arxiv_https___arxiv_org_abs_2404_10669
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Arsenic diffusion in MOVPE-Grown GaAs/Ge epitaxial structures
Orejuela, V.
Garcia-Tabares, E.
Rey-Stolle, I.
Garcia, I.
Materials Science
Applied Physics
Germanium is reemerging as a prominent material in the semiconductor field, particularly for electronic applications, photonics, photovoltaics and thermophotovoltaics. Its combination with III-V compound semiconductors through epitaxial growth by metal organic vapor phase epitaxy (MOVPE) is instrumental and thus, the comprehension of the sequential stages in such epitaxial processes is of great importance. During the deposition of GaAs on p-type Ge, the formation of n/p junctions occurs when As diffuses into Ge. It is found that this formation begins in the so-called AsH3 preexposure where Ge substrate is firstly exposed to AsH3. Also important is the fact that both free carrier profiles and As profiles indicate that prolonged AsH3 preexposure times lead to deeper diffusion depths for the same process time. This effect is concomitant with the degradation of the Ge surface morphology, characterized by higher roughness as the AsH3 preexposure duration is extended. Contrary to ion-implanted As in germanium, which shows quadratic dependent diffusivity, our MOVPE investigation using AsH3 indicates a linear relationship, consistent with Takenaka et al.'s MOVPE study using TBAs. Analyzing As profiles alongside simulations, with and without subsequent GaAs epitaxy, suggests the generation of Ge vacancies during the process, contributing to deeper As diffusion.
title Arsenic diffusion in MOVPE-Grown GaAs/Ge epitaxial structures
topic Materials Science
Applied Physics
url https://arxiv.org/abs/2404.10669