Hexamethyldisilane/propane versus silane/propane precursors: application to the growth of high-quality 3C–SiC on Si

Abstract

From a comparative evaluation of hexamethyldisilane (HMDS) and silane-propane (SP) precursor systems, it is shown that HMDS needs a small addition of propane to deposit heteroepitaxial layers of 3C-SiC on Si with superior crystalline properties. In this case, propane compensates for the secondary reactions induced by hydrogen reacting with carbon. Using atmospheric pressure chemical vapour deposition conditions, the new system (HMDS-propane) demonstrates several advantages. It is safer to handle than SP and allows a higher growth rate (up to 7 µm h −1 at 1350 • C) without any degradation of the layer morphology. However, when lowering the deposition temperature, HMDS is revealed to be more stable than silane. This is in contrast to most standard beliefs but explains why a high temperature (∼1350 • C) is always necessary to grow high-quality material using HMDS.

Influence of Carbonization Conditions in Hydrogen Poor Ambient Conditions on the Growth of 3C-SiC Thin Films by Chemical Vapor Deposition with a Single-Source Precursor of Hexamethyldisilane

“…According to the C 3 H 8 flow rate, the root mean square (RMS) roughnesses were 2.5, 1.3, and 3.2 nm, respectively. The optimal case was 8.3 sccm, and the C/Si ratio in the gas phase was 3.5, which corresponds with literature [15]. However, the crystallinity at this ratio (õ 3.5, C 3 H 8 flow rate of 8.3 sccm) was worse than the 4 sccm case.…”

CBr4 as precursor for VPE growth of cubic silicon carbide

“…At 1250 °C the hillocks are more dense (0.15 islands/μm 2 compared 0.045 islands/μm 2 at 1200 °C, as measured by SEM statistics) but smaller (0.21 μm 3 average island volume compared to 1.7 μm 3 at 1200 °C, reduced of more than 85%), therefore the total coverage (island density x island average volume) is decreasing with temperature. This is a rather uncommon behaviour in 3C-SiC epitaxy on Si using SiH 4 and C 3 H 8 precursors: the growth rate with constant precursor partial pressure is usually found to increase with temperature in the range of 1000-1350°C [19][20][21]. The decreasing trend observed here using CBr 4 precursor could indicate a SiC growth rate thermodynamically limited at temperatures higher that 1200°C.…”

Epitaxial growth of 3C–SiC on Si(111) and (001) by laser CVD

“…Figure shows the relationship between the R dep and the T dep of epitaxial <111> and <001>‐3C–SiC films by laser CVD and other CVD processes in literatures using HMDS as single precursor. The highest R dep was 12.32 and 15.56 μm/h for epitaxial <111> and <001>‐3C–SiC films, 2‐20 times as high as that of 3C–SiC epitaxial on Si(111) and Si(001) using HMDS as precursor by conventional CVD methods . In our previous study, the diode laser not only plays a role of pyrolytic source, but also has a photolytic effect to enhance chemical reaction, which can enhance the R dep .…”