Study of the consequence of excess indium in the active channel of InGaAs/InAlAs high electron mobility transistors on device properties

Abstract
A study of the properties of In0.52Al0.48As/In0.53+xGa0.47−xAs high electron mobility transistors is carried out for 0%, 7%, and 12% excess In values in the channel. Theoretical analysis shows that the enhanced In causes a biaxial compressive strain of 0.49% to 0.84% in the channel, increases the band-edge discontinuity from 0.437 to 0.500 eV, and reduces the carrier mass by 6%. Experimental characterizations support the theoretical predictions by demonstrating an increase of mobility from 9900 to 11 200 cm2/V s at 300 K, and a transconductance enhancement from 160 to at least 230 mS/mm.