A new MIS Interface Control Technology for Fabrication of High Spatial Resolution InGaAs Change Coupled Devices for Imaging

对于包括HDTV在内的先进图像技术，需要空间分辨率远高于当今标准的固态成像设备。传统Si CCD的空间分辨率不受光刻的限制，而是受其间接带隙性质的限制，这使得光学吸收层不可避免地变厚，从而由于载流子扩散而导致图像模糊。这种困难可以通过使用直接能隙材料如InGaAs来克服。然而，化合物半导体MIS界面通常具有高的能隙态密度，这给MIS器件的实现带来了困难，本研究的目的是建立一种新的实用的MIS界面控制技术，用于InGaAs MIS CCD的制作。主要成果如下：（1）新技术采用了硅基硅界面控制层（SiICL）。基本步骤包括InGaAs的MBE生长、在InGaAs上MBE生长Si ICL、Si ICL的部分氧化和光CVD Si的淀积 ...更多信息 O_2层用ArF准分子激光。在这种结构中，Si ICL通过Si原子的赝晶排列终止InGaAs的表面键，从而实现向外部厚SiO_2层的平滑过渡。SiICL的必要条件是：（a）保持与InGaAs的赝晶匹配;（B）防止InGaAs直接氧化;（c）形成低氧化物组分少的SiO_2/Si界面。(2)利用原位XPS监测，建立了一个包括重复沉积-氧化-退火循环的优化工艺，该工艺同时实现了上述三个条件，并降低了N_（<ss>？）(3)通过HF处理将表面化学计量改变为富As条件，随后通过Si ICL还原富As氧化物，本发明的Si ICL技术已经与其中样品表面暴露于空气是不可避免的常规器件处理技术兼容。(4)新的硅ICL技术已成功地应用于凹槽栅耗尽型MISFET和MIS CCD结构的制造，其最大沟道迁移率为3850 cm ^2/V. s。和非常小的电流漂移。(5)新的硅ICL技术也已被应用于InGaAs线结构的钝化，GaAs肖特基势垒高度超过400 meV的控制和异质结带的控制。少

For advanced image technologies including HDTVs, solid state imaging devices whose spatial resolution is much higher than today's standard is required. The spatial resolution of conventional Si CCDs is limited not by lithography, but by its indirect bandgap nature which makes the optical absorption layer inevitably thick, causing smearing of images due to carrier diffusion. This difficulty can be overcome by using a direct energy gap materials like InGaAs. However, compound semiconductor MIS interfaces generally possess high density of gap states which makes realization of MIS devices difficult.The purpose of the present research was to establish a new practical MIS interface control technology for fabrication of InGaAs MIS CCDs. The main achievements are listed below :(1) The new technology uses a ultrathin Si interface control layer (Si ICL). The basic sequence consists of MBE growth of InGaAs, MBE growth of Si ICL on InGaAs, partial oxidation of Si ICL and deposition of photo-CVD Si … More O_2 layer using ArF excimer laser. In this structure, the Si ICL terminates surface bonds of InGaAs by a pseudomorphic array of Si atoms which make in turn a smooth transition to a outer thick SiO_2 layer. The necessary conditions for Si ICL are (a) maintenance of its pseudomorphic matching to InGaAs, (b)its capability of prevention of direct oxidation of InGaAs and (c) formation of a good SiO_2/Si interface with minimal suboxide components.(2) Using in-situ XPS monitoring, an optimized process involving a repeated deposition-oxidation-annealing cycle has been established which simultaneously achieves the above three conditions, and reduces N_<ss>.(3) By changing the surface stoichiometry towards As-rich condition by HF treatment and subsequently reducing As-rich oxide by Si ICL, the present Si ICL technology has been made compatible with the conventional device processing technology where exposure of sample surface to air is inevitable.(4) The new Si ICL technology has been successfully applied to fabrication of recessed gate depletion mode MISFETs and MIS CCD structures with the maximum channel mobility of 3850 cm^2/V.s. and a very small current drift.(5) The new Si ICL technology has also been applied to passivation of InGaAs wire structures, control of GaAs Schottky barrier heights over 400 meV and control of heterojunction band line-up. Less