"Fabrication of high-speed and low-power-consumption InP-based HEMT by novel interface control techniques"

本研究的目的是采用原位电化学方法制作肖特基栅高功率InAlAs/InGaAsHEMT，并采用超薄Si界面控制技术制作低功耗的绝缘栅InAlAs/InGaAsHEMT。获得的主要结果如下：(1)一种新的原位脉冲模式电化学工艺使我们能够在InP、InAlAs和InGaAs上形成良好的肖特基接触.(2)溅射形成的Ti/n-InP接触在500ﾟC快速热退火后表现出良好的欧姆特性.(3)SiN/SiIn-InP结构的最小界面态密度低至2×10^-lt；10-gT；采用ECR N_2等离子体外延生长超薄Si界面控制层，并对其进行部分氮化处理。(4)在1 Hz至微波频率范围内，观察到钝化InGaAs结构的小信号响应。基于无序诱导能隙态(DIGS)模型，可以很好地将复杂的频率依赖关系拟合到等效电路中。(5)利用Si界面控制层实现了一种新型的绝缘栅InAlAs/InGaAsHEMT结构。得到的最小界面态密度为2×1010 cm~(-2)~(-2)·ev~(-1)·t~(-1)。(6)与不加Si层的HEMT相比，有Si界面控制层的HEMT的跨导Gm提高了10倍以上。

The purpose of this study is to fabricate a high-speed InAlAs/InGaAs HEMT with Schottky gate using in-situ electrochemical process and to fabricate an insulated-gate InAIAs/InGaAs HEMT with low-power consumption using ultrathin Si interface-control technique. The main results obtained are listed below :(1) A novel in-situ pulsed-mode electrochemical process enables us to produce good Schottky contacts on InP, InAlAs and lnGaAs with carrier transport properties according to the thermionic emission model.(2) A Ti/n-InP contact formed by sputtering showed good ohmic characteristics after rapid thermal annealing at 500 ﾟC.(3) A SiN/SiIn-InP structure with the minimum interface state density as low as 2x 10^<10> cm^<-2> was successfully fabricated by epitaxial growth of ultrathin Si interface control layer and its partial nitridation using ECR N_2 plasma.(4) A small-signal response of a passivated InGaAs structure was observed over a wide frequency range from 1Hz to microwave frequencies. The complicated frequency dependence of the MIS admittance can be well fitted into an equivalent circuit based on the disorder-induced gap state (DIGS) model.(5) A novel insulated gate InAlAs/InGaAs HEMT structure was realized by use of Si interface control layer. The minimum interface state density of 2x1010 cm^<-2> eV^<-1> was achieved.(6) It was found that a transconductance gm of the fabricated HEMT with the Si interface controllayer was enhanced more 10 times than that of the HEMT without Si layer.