Halide Vapor Phase Epitaxy of Ge from an Elemental Source
Year: 2025
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide Halide vapor phase epitaxy shows promise for low-cost photovoltaic device manufacturing because of its high growth rates and lower cost elemental precursors but previously has not been used to deposit epitaxial Ge. Here, we demonstrate Ge deposition by generating GeCl 2 in situ from solid Ge and HCl in a N 2 ambient. To achieve Ge growth, we inject AsH 3 and PH 3 as sources of active hydrogen to the growth surface to create a driving force for growth. We do not observe Ge growth unless a supply of hydrogen is added, consistent with thermodynamic calculations. Furthermore, we show the hydrogen source must crack readily on the substrate surface to enable growth; relatively stable sources such as H 2 do not cause growth. Unintentional group V doping is one drawback of using AsH 3 and PH 3 to drive the Ge reaction. We observed As or P concentrations in the Ge films ranging from 4 × 10 17 to 1 × 10 18 atoms/cm 3, concentrations that can drastically influence device characteristics. However, we note there are numerous other “helper molecule” options that can provide active hydrogen without doping or etching the material. This work provides a path forward for Ge deposition for optoelectronic devices from an elemental source.
Source: Crystal Growth & Design
Institutions: National Laboratory of the Rockies, Amherst College
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
Funder: Air Force Research Laboratory
OpenAlex ID: W4407857234