Self-consistent analysis of AlSb/InAs high electron mobility transistor structures

Abstract

The influences of channel layer width, spacer layer width, and δ-doping density on the electron density and its distribution in the AlSb/InAs high electron mobility transistors (HEMTs) have been studied based on the self-consistent calculation of the Schrödinger and Poisson equations with both the strain and nonparabolicity effects being taken into account. The results show that, having little influence on the total two dimensional electron gas (2DEG) concentration in the channel, the HEMT’s channel layer width has some influence on the electron mobility, with a channel as narrow as 100–130 Å being more beneficial. For the AlSb/InAs HEMT with a Te δ-doped layer, the 2DEG concentration as high as 9.1×1012 cm−2 can be achieved in the channel by enhancing the δ-doping concentration without the occurrence of the parallel conduction. When utilizing a Si δ-doped InAs layer as the electron-supplying layer of the AlSb/InAs HEMT, the effect of the InAs donor layer thickness is studied on the 2DEG concentration. To obtain a higher 2DEG concentration in the channel, it is necessary to use an InAs donor layer as thin as 4 monolayer. To test the validity of our calculation, we have compared our theoretical results (2DEG concentration and its distribution in different sub-bands of the channel) with the experimental ones done by other groups and show that our theoretical calculation is consistent with the experimental results.