掺In半绝缘GaAs衬底上外延GaAs的晶格失配研究

Study of Lattice Mismatch in GaAs Epilayers Grown on SI GaAs: In Substrate

本文报道了在掺In半绝缘GaAs衬底上的液相和汽相外延生长,并用x射线双晶衍射和光学显微等方法研究外延层和衬底之间的晶格失配.结果表明,当衬底中In组分x<0.004时,外延层失配应力主要由弹性形变调节,不出现失配位错,并可得到很好的表面形貌;当x≥0.006时,外延层产生失配位错,失配应力主要由失配位错调节,液相外延层表面出现沿[110]和[110]方向的十字网络.当外延层产生范性形变时衬底中的临界In组分x_c在0.004和0.006之间.

The LPE and VPE growth of GaAs on SI GaAs:In (001) substrate is reported.Thelattice mismatch between epilayer and substrate has been studied by double crystal X-ray dif-fraction and optical photographic methods.The results show that no misfit dislocation is gene-rated during growth when the In composition X in substrate is less than 0.004, the misfit straininduced by the lattice mismatch is accommodated mainly by elastic deformation, and good sur-face morphologycould be obtained:When the In composition X exceeds 0.006, misfit disloca-tions are found to be generated, the relaxation of the misfit strain is caused mainly by misfitdislocations,and 'Cross-hatch' pattern appeared along [110] and [110] directions in theLPE layer surface. The critical composition X_c of In for plastic deformation of epilayer isbetween 0.004 and 0.006.