Low Temperature Lateral Epitaxial Growth of Silicon Carbide on Silicon
- PDF / 1,349,366 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 56 Downloads / 278 Views
Low Temperature Lateral Epitaxial Growth of Silicon Carbide on Silicon. Chacko Jacob, Juyong Chung1, Moon-Hi Hong1, Pirouz Pirouz1 and Shigehiro Nishino Dept. of Electronics and Information Science, Kyoto Institute of Technology, Kyoto, 606-8585, Japan 1 Dept. of Materials Science and Engineering, Case Western Reserve University, Cleveland, OH 44106, U.S.A. ABSTRACT To reduce the defect density inherent in conventional heteroepitaxial growth of SiC on Si, selective epitaxy followed by lateral epitaxial growth was performed in a conventional atmospheric pressure chemical vapor deposition (APCVD) system. The source gas was primarily hexamethyldisilane (HMDS). Hydrogen was used as the carrier gas and small amounts of hydrogen chloride (HCl) were added to improve the selectivity. Si(001) wafers, with an oxide layer (~ 700 nm thick) as a mask, were used as substrates. The grown films were analyzed using optical microscopy and scanning electron microscopy (SEM). In earlier work, we had demonstrated the problems associated with the application of this technique - viz., oxide degradation and high growth temperature. Using HMDS, the growth temperature has been considerably reduced allowing the continued use of an oxide mask. Selective growth was demonstrated in films grown at 1250°C and below.
INTRODUCTION
Due to the rapid development of 6H- and 4H-SiC substrates, the development of 3C-SiC has been relatively slow. Some attempts at growing 3C-SiC on 6H-SiC substrates continue while recognizing that the presence of double-positioning boundaries (DPBs) are a major concern. While homoepitaxial growth of 3C-SiC has not developed, heteroepitaxial growth of 3C-SiC on Si [1] and other substrates [2] has indicated promise. Nevertheless, the high density of interfacial defects (misfit dislocations, voids) as well as other defects (threading dislocations) result in the growth of lower quality material. One of the promising approaches to solving this problem is selective epitaxial growth on patterned substrates followed by epitaxial lateral overgrowth. The main factors affecting selective epitaxy on Si were temperature of growth, choice of mask material, orientation of windows, mask to window ratio, influence of an etchant (e.g. HCl), quality of the mask material, etc. [3]. In applying this technique to SiC growth, Edgar et al [4] report that a limiting factor is the oxide stability as well as the duration of growth. For long growth times, it was difficult to suppress unwanted nucleation on the oxide. Nishino et al [5] also reported that the use of HCl aided the process of selective epitaxy. More recently, Saddow et al [6] reported some preliminary work on the selective epitaxy of SiC on Si using silicon nitride and aluminum nitride as masks. However, there was no evidence of selectivity using either mask. Our earlier work [7] reported the use of hexachlorodisilane (HCDS) and propane as the source materials and an oxide mask to demonstrate selective epitaxy and lateral overgrowth (Figure 1). T4.1.1
The limitations of using the oxid
Data Loading...
