Plasma-assisted epitaxial growth of GaAs and GaSb layers in hydrogen plasma

Plasma-assisted epitaxy has been successfully applied to grow device-quality GaAs and GaSb layers on semi-insulating GaAs at relatively low substrate temperatures. Nondoped GaAs layers deposited in argon and hydrogen plasma showed p- and n-type conduction, respectively. The mobility in As-grown nondoped n-layers deposited in hydrogen plasma at a substrate temperature of 550°C is 3200 cm²/V . s. Nondoped GaSb layers deposited in argon and hydrogen plasma both showed p-type conduction. Hole concentration and Hall mobility of an undoped GaSb layer deposited in hydrogen plasma at a substrate temperature of 410°C are about cm^-3and 750 cm²/V . s, respectively, which are comparable to those obtained by other methods like MBE, MOCVD, etc., in spite of a lower substrate temperature in PAE. As the substrate temperature is decreased, optimum plasma power for the growth of good epitaxial layers shifts to higher value. PAE in hydrogen plasma was found to give much better results than in argon plasma, as indicated by lower carrier concentration, higher Hall mobility, and clear edge emission in photoluminescence.