Influence of strain compensation in InAlAs/InGaAs pseudomorphic HEMTs on InP

摘要

InAlAs/InGaAs pseudomorphic HEMTs suffer from two drawbacks which can impede their future developments: a mechanical instabiity of their strained layers and a low breakdown voltage. In this wor, we study pseudomorphic structures where the channel and the space are strain compensated: the InGaAs channel is compressively strained and the InAlAs spacer is tensilely strained. This structure along with a non compensated reference are annealed up to 600 deg C and photoluminescence measurements show that the compensated structure is more stable than the non compensated one. HEMTs processes on these structures exhibit a higher breakdown voltage on the compensated structure, related to a higher velence band offset.