Growth of Columnar SiC on Patterned Si Substrates by CVD
- PDF / 592,243 Bytes
- 6 Pages / 595 x 842 pts (A4) Page_size
- 31 Downloads / 251 Views
K1.7.1
GROWTH OF COLUMNAR SiC ON PATTERNED Si SUBSTRATES BY CVD Shigehiro Nishino, Yoichi Okui, Yuehai Tai and Chacko Jacob* Department of Electronics and Information Science, Faculty of Engineering and Design, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585 Japan *Materials Science Center, Indian Institute of Technology, Kharagpur, India 721 302
ABSTRACT Single crystalline 3C-SiC films have been grown on Si(111) substrate at 1200oC by conventional CVD process using HMDS (Hexamethyldisilane). Before columnar growth of SiC, columnar Si was made by depositing Au on Si(111) substrate as a solvent of VLS mechanism. Si growth was carried out by disproportional reaction in halide transport method. The columnar Si was produced on the patterned substrates. The columnar Si was covered by SiC. Needle like columns of SiC can be used for MEMS application such as micro-heat exchanger. INTRODUCTION The heteroepitaxial growth of 3C-SiC on Si and other substrates has indicated the promise of high mobility devices and also application for MEMS. In MEMS application, a suitable approach is the use of selective epitaxial growth of Si and SiC on patterned silicon substrates. The substrates used were patterned silicon substrates prepared by depositing a SiO2 layer as the mask, followed by conventional lithographic techniques. The windows are of different shapes (square, circle, hexagonal, parallel lines). Gold was deposited on the patterned Si substrates using conventional vacuum evaporation. Selective growth of Si was carried out in close space technique by halides (HCL) transport method in H2 atmosphere at around 1200ºC. A columnar structure of Si was automatically produced on the patterned substrate by VLS mechanism. The columnar Si is used for MEMS application [1]. To deposit SiC film on columns , a horizontal atmospheric pressure chemical vapor deposition reactor was used. An initial carbonization procedure was performed using 1 sccm propane at 1250oC for 2-3 minutes. During the growth of SiC, the flow rate of HMDS was 0.1-0.75 sccm and the flow rate of H2 was 3 slm. SiC covered Si columns is applicable to MEMS devices. When the Si inside of the SiC is dissolved, the micropipes will be obtained. Those micropipes will be used for heat-exchanger of micromachines.
K1.7.2
EXPERIMENT Selective deposition of Si was carried out by the atmospheric pressure chemical vapor deposition as following way. Si substrate was patterned using conventional photolithography. Based on close-spaced vapor transport technique developed by Nicoll, we develop a fairly rapid growth of single crystal Si on patterned Si substrate [2,3]. The Si substrate and source Si wafer were set face to face with small space. Sources of Si wafer was etched by HCL and transported to the Si substrate spacing about 400 µm. The source Si wafer was on the susceptor. In this configuration, source temperature was higher than the substrate. Spacings of 400 µm were quite satisfactory in giving specular surface of epilayer on flat substrate. For selective epi
Data Loading...
