This paper is for the simulation design to enhance the breakdown voltage of MHEMTs with an InP-etchstop layer. Gate-recess and channel structures has been simulated and analyzed for the breakdown of the MHEMT devices. The fully removed recess structure at the drain side of MHEMT shows that the breakdown voltage enhances from 2 V to almost 4 V as the saturation current at gate voltage of 0 V is reduced from 90 ㎃ to 60 ㎃ at drain voltage of 2 V. This is because the electron-captured negatively fixed charges at the drain-side interface between the InAlAs barrier and the Si₃N₄ passivation layers deplete the InGaAs channel layer more and thus decreases the electron current passing the channel layer and thus the impact ionization in the channel become smaller. In addition, the replaced InGaAs/InP composite channel with the same thickness in the same asymmetrically recessed structure increases the breakdown voltage to 5 V due to the smaller impact ionization and mobility of the InP layer at high drain voltage.

Keywords: HEMT,메타몰픽-HEMT (MHEMT),소자 시뮬레이션,차단주파수,최대진동주파수,항복전압,Metamorphic HEMT (MHEMT),Device simulation,Cutoff frequency,Maximum oscillation frequency,Breakdown