Control of the conduction mechanism via the formation of native defects in RF-magnetron-sputtered GaSb thin films on Ge(100) substrates

• Published in: Journal of crystal growth 2017-06, Vol.468, p.732-736
• Main Authors: Nishimoto, Naoki, Fujihara, Junko, Yoshino, Katsumi
• Format: Article
• Language: English
• Subjects: A1. Defects; A3. Physical vapor deposition processes; B1. Antimonides; B1. Gallium compounds; B2. Semiconducting gallium compounds; Chemical compounds; Conductivity; Crystal defects; Crystal structure; Magnetron sputtering; Quartz; Strain relaxation; Substrates; Thin films
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2016.11.082

GaSb thin films were grown on quartz substrate and Ge(100) 1°-off-axis substrate by RF magnetron sputtering at growth temperatures of 400, 500, and 600°C. The crystalline quality of GaSb/quartz improved with increasing growth temperature. The GaSb/Ge(100) grown at 500°C exhibited good crystalline quality with comparatively high mobility (219cm2/Vs); however, the mobility degraded in GaSb/Ge(100) films grown at higher temperatures because of the increase in crystal defects induced by strain relaxation. Undoped GaSb has been previously reported to always exhibit p-type conductivity, irrespective of the growth method and growth conditions. However, we prepared an undoped GaSb thin film with n-type conductivity by using a Ge(100) 1°-off-axis substrate. This finding led to the conclusion that the use of an off-axis substrate affects the defect formation mechanism and enables the control of the conduction mechanism in undoped GaSb thin films. •GaSb thin films are grown epitaxially on a Ge(100) 1°-off-axis substrate.•GaSb thin films on a Ge(100) 1°-off-axis substrate shows n-type conductivity.•n-GaSb with n≥1.64×1017cm−3 and p-GaSb with p≥1.44×1019cm−3 are degenerate.•Using an off-axis substrate is effective for undoped GaSb thin film.