Heteroepitaxial growth of gallium antimonide on GaAs by low pressure MOVPE

Abstract

Undoped GaSb epilayers have been grown on (100) GaAs semi-insulating substrates by low pressure metalorganic vapor phase epitaxy (MOVPE). The effects of growth temperatures and TMSb/TEGa mole fraction ratios on the epitaxial properties of surface morphology, growth rate, carrier concentration and hole mobility (measured at 300 and 77 K) have been studied. For TMSb/TEGa mole fraction ratio of 6.84, a smooth surface morphology can be obtained at growth temperature of 550°C. At 550°C, the epitaxial surface grown for V/ III = 6.64 was more smooth and mirror-like than that grown for V/ III = 6.84. The growth rate increases with growth temperature. The hole concentration increases and mobility decreases with growth temperature between 520 and 635°C for V/ III = 6.84. For 550°C grown epilayers: as the V/III ratio increased above 6.64 or decreased below 6.64, the hole concentration increased and the hole mobility decreased. The lowest concentration 1.8 × 10 16 cm −3 (77 K) and the highest mobility 1447 cm 2/V s (77 K) can be obtained for a V/III ratio of 6.64 at 550°C.