All in-situ GaSb MOS structures on GaAs (001): Growth, passivation and high-k oxides

• Published in: Journal of crystal growth 2013-09, Vol.378, p.631-635
• Main Authors: Tokranov, V., Madisetti, S., Yakimov, M., Nagaiah, P., Faleev, N., Oktyabrsky, S.
• Format: Article
• Language: English
• Subjects: A1. Surface structure; A3. Molecular beam epitaxy; Aluminum oxide; B1. Antimonides; B1. Oxides; B2. Semiconducting III–V materials; Cross-disciplinary physics: materials science; rheology; Crystal growth; Density; Deposition; Exact sciences and technology; Gallium arsenide; Hafnium oxide; Materials science; Metal oxide semiconductors; Methods of crystal growth; physics of crystal growth; Methods of deposition of films and coatings; film growth and epitaxy; Molecular, atomic, ion, and chemical beam epitaxy; Oxides; Passivation; Physics; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2012.12.105

The GaSb-on-GaAs growth was optimized for the fabrication of metal-oxide-semiconductor (MOS) capacitors (Caps) with low interface state trap density (Dit) using in-situ deposited amorphous silicon (a-Si) interface passivation layer (IPL) and high-k oxides. The best top surface with the average roughness Ra=0.37nm and with spiral type “step-flow” growth mode was observed in the GaSb structure with the initial 0.5μm grown at 410°C and the top 0.5μm grown at 485°C. N- and p-type GaSb MOSCaps with reasonable capacitance–voltage(C–V) characteristics at room temperature (RT) were demonstrated using all in-situ 0.5nm a-Si IPL and 10nm Al2O3+HfO2 or Al2O3. A-Si IPL was found essential for n-MOSCaps but not in the case of p-MOSCaps where comparable C–V characteristics with a similarly low Dit=1–2×1012cm−2eV−1were demonstrated without IPL. ► The GaSb-on-GaAs growth was optimized for the fabrication of MOSCaps with low Dit. ► The top surface with “step-flow” growth mode and Ra=0.37nm was obtained. ► All in-situ deposited a-Si IPL and high-k oxides were used in MOSCaps. ► N-/p-type GaSb MOSCaps with reasonable C–V characteristics at RT were demonstrated. ► A-Si IPL was found essential for n-MOSCaps but not in the case of p-MOSCaps.