Silicon interlayer based surface passivation of near-surface quantum wells

Abstract

In view of the urgent necessity to establish a suitable passivation technology applicable to compound semiconductor quantum structure surfaces, the latest version of the silicon interlayer based passivation process was applied to passivation of Al0.3Ga0.7As/GaAs/Al0.3Ga0.7As near-surface quantum wells (QWs). The process utilizes an ultrathin molecular beam epitaxy silicon/ultrathin photo-enhanced chemical vapor deposition (photo-CVD) silicon nitride double layer as the interface control layer together with a main passivation dielectric of thick photo-CVD SiO2 layer. The effectiveness of passivation was studied by comparing the photoluminescence (PL) intensities of passivated samples with those of unpassivated QWs that showed exponential decrease with reduction of surface-to-well distance. A complete recovery of PL intensity was achieved by passivation with a maximum recovery factor larger than 103, consistent with reduced interface state densities in low 1010 cm−2 eV−1 range recently realized on In0.53Ga0.47As metal–insulator–semiconductor capacitors using the same technique.