Pattern-recessed ohmic contacts are investigated for InAlGaN/GaN high-electron-mobility transistors (HEMTs). Periodically-recessed patterns are introduced in the source and drain contact area to achieve the lower contact resistance by making sidewall contact as well as top contact on the active mesa. The lowest ohmic contact resistance (R_c) of 0.19 Ω·mm is achieved. It is significantly lower than the contact resistance of 0.29 Ω·mm, which is obtained from the conventional ohmic contact without recessed pattern. When the proposed ohmic contact scheme is introduced in 3-μm-long gate HEMTs, the on-resistance and the maximum transconductance are improved from 2.41 Ω·mm and 320 mS/mm to 2.24 Ω·mm and 332 mS/mm, respectively. The unity current gain cut-off frequency (f_T) and the maximum oscillation frequency (f_max) of the device is increased from 2.78 and 10.05 GHz to 2.97 and 10.65 GHz, respectively.

研究了用于InAlGaN / GaN高电子迁移率晶体管（HEMT）的图案凹陷的欧姆接触。通过在有源台面上进行侧壁接触和顶部接触，在源极和漏极接触区域引入周期性凹陷的图案，以实现较低的接触电阻。最低的欧姆接触电阻（R _c）为0.19Ω·mm。它远低于0.29Ω·mm的接触电阻，后者是从没有凹陷图案的常规欧姆接触获得的。当将建议的欧姆接触方案引入3μm长的栅极HEMT中时，导通电阻和最大跨导分别从2.41Ω·mm和320 mS / mm分别提高到2.24Ω·mm和332 mS / mm。单位电流增益截止频率（f _T），并且装置的最大振荡频率（f _max）分别从2.78和10.05 GHz增加到2.97和10.65 GHz。