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

本研究的目的是利用原位电化学工艺制备高速肖特基栅InAlAs/InGaAs HEMT，并利用超薄Si界面控制技术制备低功耗绝缘栅InAIAs/InGaAs HEMT。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根据热离子发射模型在InP， InAlAs和lnGaAs上产生具有载流子输运性质的良好肖特基触点。(2)溅射形成的Ti/n-InP触点经500℃快速热退火后，具有良好的欧姆特性。(3)利用ECR N_2等离子体外延生长超薄Si界面控制层并进行部分氮化，成功制备出最小界面态密度为2x 10^<10> cm^<-2>的SiN/ SiN - inp结构。(4)钝化InGaAs结构在1Hz到微波频率范围内具有小信号响应。基于无序诱导隙态（DIGS）模型的等效电路可以很好地拟合MIS导纳复杂的频率依赖性。(5)利用Si接口控制层实现了一种新型绝缘栅InAlAs/InGaAs HEMT结构。最小界面态密度为2x1010cm ^<-2> eV^<-1>。(6)发现有Si界面控制层的HEMT的跨导系数比没有Si界面控制层的HEMT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.