InP HEMT空腔栅结构器件制备及性能

Preparation and Performances of InP HEMT Device with Cavity Gate Structure

InP HEMT具有优异的高频特性以及良好的散热、击穿和噪声性能,已成为太赫兹应用领域的重要器件之一。工程化应用要求器件具有厚的钝化保护层,厚钝化层又导致器件频率特性变差。针对这一问题,在自主的工艺线上制备了源漏间距2.5μm、栅长100 nm的T型栅InP基InAlAs/InGaAs HEMT。通过采用高In组分的InGaAs沟道层提升了该层的载流子迁移率和器件的直流跨导,最大直流跨导为1700 mS/mm;通过制作空腔结构解决了厚钝化层带来的栅寄生电容大的问题,器件频率特性有很大提升,截止频率为300 GHz,最大振荡频率为700 GHz。微波测试结果表明,该器件在加厚钝化保护层后依然保持了良好的频率特性,可用于220 GHz放大器工程化应用领域。

InP HEMT has excellent high frequency characteristics,good heat dissipation,breakdown and noise performances,and has become one of the most important devices in terahertz frequency application field.Engineering applications require devices to have thick passivation protective layer,which leads to poor frequency characteristics of devices.To solve this problem,the T-gate InP-based InAlAs/InGaAs HEMTs with the gate length of 100 nm and the source-drain space of 2.5μm were successfully prepared on the independent process line.The carrier mobility of the channel layer and DC transconductance of device were improved by adopting high In composition of InGaAs channel layer,and the maximum DC transconductance is 1700 mS/mm.By making a cavity structure,the problem of large parasitic capacitance of the gate caused by thick passivation layer was solved.The frequency characteristics of the device were greatly improved,with a cutoff frequency of 300 GHz and a maximum oscillation frequency of 700 GHz.The microwave test results show that the device still retains good frequency characteristics after thickening the passivation protective layer,and can be used in 220 GHz amplifier engineering application fields.