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

Abstract

Dielectric-cap quantum-well disordering of GaAs-AlGaAs multiple-quantum-well (MQW) structure was carried out using SiNx capping layer grown by plasma enhanced chemical raper deposition. There was a dependence of quantum-well disordering (QWD) on the hydrogen content in the SiNx capping layer, which was varied by changing the NH3 how rate during the film growth, The degree of QWD increased with increasing of hydrogen content in the SiNx capping layer, The degree of QWD with SiNx capping laver grown at higher NH3 how rate was comparable to that with a 300-mn-thick SiO2 capping layer at the same rapid thermal annealing condition. This result implies the possibility of obtaining spatially selective disordered MQW structure using SiNx capping layers grown at different NH3 how rates. The effect of different SiNx cappings layers on QWD was characterized semiquantitatively by introducing relative vacancy density.