Wavelength tunable UV laser stimulated growth of Al/sub x/Ga/sub 1-x/ by OMVPE

UV stimulated OMVPE growth of AlGaAs from TMG, TMA and arsine at 500/spl deg/C was studied using a wavelength tunable pulsed laser in the range from 235 nm to 255 nm. We observe an abrupt wavelength edge at 252 nm, below which the stimulation rate is constant and above which the growth enhancement ceases. We demonstrate a high growth contrast of 3.2:1 and show that the growth enhancement is due to photostimulation of the adlayer. The formation of a periodic surface structure agrees with theory and results in growth directions deviating from [100]. Good crystal quality was determined by Raman spectroscopy.