ABSTRACT
High quality GaAs heteroepitaxial layers have been grown on Si (001) substrates 4° off toward [110] direction by the combination of two step growth, thermal cycle annealing (TCA) and Si doping using MBE. The omega /2theta rocking curves of 3pm thick GaAs and Si substrates have been recorded both parallel and perpendicular to the direction of stair case steps formed by the misorientation of the substrate. Heavy doping of Si improves the crystalline quality of GaAs from 205 to 174 arc-sec as estimated from the double crystal XRDFWHM. The crystallographic tilt in the epitaxial layers along [110] direction decreases on increasing the doping concentration of Si and the temperature of TCA. The electrochemical etch profding and SIMS analysis revealed the compensation of Si. The increase in tensile strain (123%) due to TCA has been observed from the difference in energy levels of the valence band splitting. The dislocation reduction has been explained by the reduction of crystallographic tilt, generation of strain and the compensation of Si in the GaAs sub-lattice.
