复合沟道氟离子增强型AlGaN/GaN HEMT的研究

Study of a Novel Hybrid-channel Enhancement-mode AlGaN/GaN HEMT

提出一种复合沟道氟离子(F-)增强型AlGaN/GaN HEMT(Hybrid-channel enhancement-mode AlGaN/GaN HEMT,HCE-HEMT)新结构。该结构引入高、低浓度F-复合沟道,其中高浓度F-注入区位于沟道靠近源漏两端以调制阈值电压,获得增强型器件;低浓度F-区位于沟道中部以调制肖特基栅电极的正向开启电压,增加器件承受的栅电压摆幅,但它对其下方二维电子气的耗尽作用很弱。同时,高浓度区只占栅长的40%,减轻高浓度F-对沟道的影响,提升器件的电流能力。利用Sentaurus软件仿真,结果显示,与传统F-增强型AlGaN/GaN HEMT相比,HCE-HEMT载流能力提高了40.3%,比导通电阻下降了23.3%,同时反向耐压仅下降了5.3%。

A novel hybrid-channel enhancement-mode AlGaN/GaN HEMT（HCE-HEMT）is proposed and investigated.The hybrid channel comprises both high concentration F-and low concentration F-,while the high concentration F-is located at both sides of the gate-controlled channel to modulate the threshold voltage of the device,resulting in a normally-off AlGaN/GaN HEMT.Meanwhile,the low concentration F-is seated in the middle of gate-controlled channel to suppress the gate forward leakage current.Due to the low concentration F-,the 2DEG under this region is weakly depleted.Moreover,the length of the high concentration F-region is optimized to be only 40%of gate length for alleviating influence of high concentration F-on channel.The simulation results show that maximum drain current density is improved by 40.3% with corresponding reduction of specific on-resistance by 23.3%in the proposed device,compared with conventional F-implanted enhancement-mode AlGaN/GaN HEMT. Furthermore, the breakdown voltage is only decreased by 5.3%.