LOW-TEMPERATURE GROWTH OF 3C-SIC FILMS ON SI SUBSTRATE

SI 衬底上 3C-SIC 薄膜的低温生长

基本信息

批准号：
11450127
负责人：
MIYASATO Tatsuro
金额：
$ 4.48万
依托单位：
KYUSHU INSTITUTE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

The quality of the cubic silicon carbide (3C-SiC) grown on a Si substrate was very poor due to the large lattice mismatch of about 20 % between 3C-SiC and Si, the relatively large difference in thermal expansion coefficients of about 8 %, and the loss of the Si substrate at high growth temperatures above 1000℃. To help overcome these problems, a SiC buffer layer was prepared on the surface of a Si substrate by carbonization of the substrate and sputtering of a SiC target before the SiC growth. The SiC buffer layer prevented the loss of the substrate, but did not solve completely the problems of lattice mismatch and difference in thermal expansion coefficients between Si and SiC.Recently, the alloying of C with Si and Si_<1-x>Ge_x has attracted attention because of its ability to control the strain associated with the lattice mismatch to Si. There are large differences in covalent radius, bond length, and bond strength among C, Si and Ge. Therefore, it is possible to release the strains … More due to lattice mismatch at the SiC/Si interface by atomic self-organized interdiffusion if a Ge_<1-x>C_x layer is prepared before the SiC growth. For example, the diffusions of C into Si and Ge into SiC may result in the decrease in lattice mismatch between SiC and Si.In this project, we studied a new growth technique for 3C-SiC on a Si substrate. The Ge_<1-0.63>C_<0.63> buffer layer with a thickness of 5 nm was prepared on the Si substrate at 600℃, and was annealed at the same temperature in hydrogen atmosphere for 30 min. 3C-SiC can be grown on the substrate with the buffer layer at 850℃.The crystallinity of the 3C-SiC film depends strongly on the thickness of the buffer layer. The maximum X-ray diffraction intensity of the 3C-SiC film at a buffer thickness of about 5 nm is observed. The improved crystallinity of the SiC film is related to the release of the SiC/Si interface strains in the buffer layer during the growth of the SiC film.The effects of the Si(001) substrate on epitaxial growth of the SiC film are relaxed in the buffer layer. The SiC grains grow 'freely', that is, its growth is not affected by the Si substrate. The orientation of the SiC grains depends on free energies for nucleation and growth of the SiC grains. Therefore, the (111) oriented SiC grains are preferentially grown in the film because of smaller free energy of the (111)-oriented SiC nuclei at low temperature. Less

由于3C-SiC与Si之间存在约20％的大晶格失配，以及约8％的较大热膨胀系数差异，因此在Si衬底上生长的立方碳化硅（3C-SiC）的质量非常差，为了克服这些问题，通过碳化衬底和溅射在Si衬底表面制备了SiC缓冲层。 SiC靶材在SiC生长之前，SiC缓冲层防止了衬底的损失，但并没有完全解决Si和SiC之间的晶格失配和热膨胀系数差异的问题。最近，C与Si和Si_<的合金化。 1-x>Ge_x因其能够控制与Si晶格失配相关的应变而受到关注。C、Si和Ge之间的共价半径、键长和键强度差异很大。如果在 SiC 生长之前制备 Ge_<1-x>C_x 层，则可以通过原子自组织相互扩散来释放由于 SiC/Si 界面处的晶格失配而产生的应变，例如，C 扩散到其中。 Si和Ge进入SiC可能会导致SiC和Si之间晶格失配的减少。在这个项目中，我们研究了一种在Si衬底上生长3C-SiC的新技术。在600℃下在Si衬底上制备厚度为5 nm的Ge_<1-0.63>C_<0.63>缓冲层，并在相同温度下在氢气气氛中退火30min，即可在其上生长3C-SiC。 3C-SiC 薄膜的结晶度很大程度上取决于缓冲层的厚度。缓冲层的最大 X 射线衍射强度。观察到缓冲层厚度约为5 nm的3C-SiC薄膜结晶度的提高与SiC薄膜生长过程中缓冲层中SiC/Si界面应变的释放有关。 Si(001)衬底上外延生长的SiC薄膜在缓冲层中是松弛的，SiC晶粒“自由”生长，即其生长不受Si衬底的影响。SiC晶粒的取向取决于自由。由于(111)取向SiC晶核在低温下的自由能较小，因此(111)取向SiC晶粒在薄膜中优先生长。