Langmuir Adsorption and Reaction Control in Process for Fabrication of Ultrasmall Group IV Semiconductor Devices

在本科学研究中，为了建立超小型IV族半导体器件的制造工艺技术，进行了扩展研究，包括原子层生长和蚀刻等朗缪尔型吸附/反应工艺的基础和应用。在原子控制工艺方面，我们利用低温超净反应气氛、氙灯快速加热和ECR等离子体低能离子辐照，实现了Si和Ge的原子层生长、400 ℃下NH_3对Si的原子层氮化、500-600 ℃下CH_4对Si（100）的原子层碳化，SiH_3CH_3在Si和Ge上的原子层吸附，P在Si和Ge上的原子层掺杂，SiGe系统的原子层分步刻蚀，氮化硅的原子层角色共享刻蚀等。这些原子级过程中的每一个已被描述的Langmuir型简单的吸附和反应的形式主义，这有助于建立一个高精度的控制过程的基础。在器件制作工艺方面，我们已经制作了超小型MOSFET，采用超自对准的超浅结形成在源/漏区，和MOSFET的SiGe外延层作为沟道。此外，我们已经开发了每个过程，如SiGe的选择性外延和P和B的原位重掺杂，重掺杂多晶硅的高选择性各向异性蚀刻，通过选择性生长W来降低源极/漏极电阻，以及通过这些单独过程的组合来实现总的超小型器件过程。这些研究结果为IV族半导体超小型器件的制造技术提供了一个基本的关键。

In this scientific research, to establish fabrication process technology of ultrasmall group IVsemiconductor devices, extended researches have been carried out including fundamentals and applications of Langmuir-type adsorption/reaction process such as atomic-layer growth and etching. As to atomically controlled processing, by utilizing a low-temperature ultraclean reaction atmosphere, flash heating by Xe lamps, and low-energy ion irradiation by an ECR plasma, we have achieved atomic layer-by-layer growth of Si and Ge, atomic-layer nitridation of Si by NH_3 at 400ﾟC, atomic-layer carbonization of Si(100) by CH_4 at 500-600ﾟC, atomic-layer adsorption of SiH3CH3 on Si and Ge, atomic-layer doping of P on Si and Ge, fractional atomic-layer etching of a SiGe system, atomic-layer role-share etching of silicon nitride, etc. Adsorption and reaction process in low temperature selective deposition of W has been also investigated by alternate supply of WF6 and SiH_4. Each of these atomic-order processes has been described by Langmuir-type simple adsorption and reaction formalism, which contributes to establish a base of a high precision control of the process. As to device fabrication process, we have fabricated ultrasmall MOSFETs utilizing super-self-aligned ultrashallow junction formation in the source/drain region, and MOSFETs with a SiGe epitaxial layer as a channel. Also, we have developed each process such as selective epitaxy of SiGe and in-situ heavy doping with P and B, highly selective anisotropic etching of heavily doped polysilicon, reduction of source/drain resistance by selective growth of W, as well as a total ultrasmall device process by combination of these individual processes. These research results supply a fundamental key to ultrasmall device fabrication technology with group IVsemiconductors.