We investigated the effects of antimony (Sb) overpressure during thermal cleaning (TC) on the surface morphology of InSb substrates using low pressure metalorganic chemical vapor deposition (LP-MOCVD). During the TC process under H2ambient, indium (In) droplets were observed inside etch pits on InSb(001) surfaces due to the Sb evaporation from InSb substrates. On the other hand, when InSb substrates were thermally cleaned under trimethylantimony (TMSb) ambient, the formation of In droplets and the etch pits were suppressed, resulting in the smooth InSb surface. The surface morphology of InSb was dependent on TC temperature. Rough surface morphology was observed at low TC temperature of 435 °C and it became smoother with increasing TC temperature. The improvement of surface morphology was caused by the surface stabilization with increasing Sb flux and the increase of adatom migration. The dependence of TMSb flow rate on the surface morphology was also investigated. The TMSb overpressure during the TC of InSb must be maintained to grow high quality InSb epitaxial layers with smooth surface using MOCVD.
Bibliographical noteFunding Information:
This work is supported by the DAPA and ADD , and by the WCU (World Class University) program through the National Research Foundation of Korea funded by the Ministry of Education, Science and Technology ( R31-2008-000–10075-0 ). We also wish to express thanks to the staff and crew of the Seoul National University SPM facility for their untiring efforts and perseverance.
- A1. Surfaces
- A3. Metalorganic chemical vapor deposition
- B1. Antimonides
- B2. Semiconducting III-V materials
- B2. Semiconducting indium compounds
- B3. Infrared devices