Lattice matched and Pseudomorphic InGaAs MOSHEMT with fT of 200GHz

We present lattice matched (LM) In_0.53Ga_0.47As MOSHEMT and pseudomorphic (PM) In_0.75Ga_0.25As MOSHEMT with gate-first process as well as their related post process annealing (PPA) effects in this paper. PM In_0.75Ga_0.25As MOSHEMT with 7nm In_0.75Ga_0.25As inserted channel promotes higher DC and RF performances due to higher electron mobility with higher indium content of the channel. MOSHEMT structure is preferred to MOSFET structure since the channel layer is moved away from the oxide/semiconductor interface by using of an In_0.52Al_0.48As barrier layer between channel and Al₂O₃ oxide. We obtain a high cut-off frequency f_T of 200GHz for a 100nm-gate-length device of PM In_0.75Ga_0.25As structure, which is 20GHz higher than the LM In_0.53Ga_0.47As MOSHEMT. The PPA process at 400°C for 1 minute in forming gas N₂H₂ brings no difference to the DC and RF performances, showing that the detrimental effect of the interface defects is attenuated by using buried channel.