Enhancement of electron mobility by preventing pit formation at the In 0.52Al 0.48As/In 0.8Ga 0.2As heterointerface using an inserted In 0.53Ga 0.47As layer

Abstract

The electron mobility of an In 0.52Al 0.48As/In 0.8Ga 0.2As structure with an In 0.53Ga 0.47As buffer is enhanced by about 15% to as high as 16,200 cm 2/V·s, as compared to a structure without an In 0.53Ga 0.47As buffer. In this In 0.52Al 0.48As/In 0.53Ga 0.47As/In 0.8Ga 0.2As structure, smooth interfaces are formed, whereas in the In 0.52Al 0.48As/In 0.8Ga 0.2As structure without the In 0.53Ga 0.47As buffer, pits are formed. Additionally, optimization of the In 0.53Ga 0.47As buffer thickness for field effect transistor (FET) application is carried out by electron mobility measurements and electron density distribution calculations. Since a short gate length, less than 0.2 μm, FET requires the electron distribution to be close to that of the gate electrode, we determined that 1 nm is the optimum thickness for the In 0.53Ga 0.47As buffer. The optimum thickness enhances the electron mobility and moves the peak position of the electron density away from the gate electrode by less than 0.6 nm, as compared to a structure without the In 0.53Ga 0.47As buffer.