In0.52(AlxGa1-x)0.48As/In0.53Ga0.47As(0****x****1) heterostructure and its application on HEMTs

Quaternary In_0.52(Al_xGa_1-x)_0.48As(0 ≦ x ≦ 1) compounds lattice-matched InP substrates were grown and characterized. The engery bandgap (E_g) of these In_0.52(Al_xGa_1-x)_0.48As compound were (0.806+0.711x) eV. The conduction band discontinuity (ΔE_c) at the In_0.52(Al_xGa_1-x)_0.48As/In_0.53Ga_0.47AS (x=0.9 and 0.75) heterojunctions was approximately (0.68 ± 0.01)ΔEg. The quaternary In_0.52(Al_0.9Ga_0.1)_0.48As/In_0.53Ga_0.47As Q-HEMTs with a gate-length of 0.8μm revealed an extrinsic transconductance (g_m) of 295 mS/mm, an f_T of 35 GHz and an f_max of 76 GHz. This Quaternary HEMT was proven to be more reliable, comparing with the conventional InAlAs/InGaAs HEMTs[1].