Dependence of dielectric-cap quantum-well disordering of GaAs-AlGaAs quantum-well structure on the hydrogen content in SiN/sub x/ capping layer

Abstract

Dielectric-cap quantum-well disordering of GaAs-AlGaAs multiple-quantum-well (MQW) structure was carried out using SiN/sub x/ capping layer grown by plasma enhanced chemical vapor deposition. There was a dependence of quantum-well disordering (QWD) on the hydrogen content in the SiN/sub x/ capping layer, which was varied by changing the NH/sub 3/ flow rate during the film growth. The degree of QWD increased with increasing of hydrogen content in the Si/sub x/ capping layer. The degree of QWD with SIN, capping layer grown at higher NH/sub 3/ flow rate was comparable to that with a 300-nm-thick SiO/sub 2/ capping layer at the same rapid thermal annealing condition. This result implies the possibility of obtaining spatially selective disordered MQW structure using SiN/sub x/ capping layers grown at different NH/sub 3/ flow rates. The effect of different SiN/sub x/ capping layers on QWD was characterized semiquantitatively by introducing relative vacancy density.