Dependence of dielectric-cap quantum-well disordering ofGaAs-AlGaAs quantum-well structure on the hydrogen content in SiNx capping layer

摘要

Dielectric-cap quantum-well disordering of GaAs-AlGaAsnmultiple-quantum-well (MQW) structure was carried out using SiNxn capping layer grown by plasma enhanced chemical vapor deposition.nThere was a dependence of quantum-well disordering (QWD) on the hydrogenncontent in the SiNx capping layer, which was varied bynchanging the NH3 flow rate during the film growth. The degreenof QWD increased with increasing of hydrogen content in the Sixn capping layer. The degree of QWD with SIN, capping layer grown atnhigher NH3 flow rate was comparable to that with an300-nm-thick SiO2 capping layer at the same rapid thermalnannealing condition. This result implies the possibility of obtainingnspatially selective disordered MQW structure using SiNxncapping layers grown at different NH3 flow rates. The effectnof different SiNx capping layers on QWD was characterizednsemiquantitatively by introducing relative vacancy density