Fluorinated SiC CVD
نویسنده
چکیده
For the emerging semiconductor material silicon carbide (SiC) used in high power devices, chemical vapor deposition (CVD) is the most prominent method to create the electrically active SiC epitaxial layers in the device. The process of growing such epitaxial layers is to use a hydrocarbon and silane diluted in hydrogen flow through a hot chamber where chemical reactions take place in such a manner that Si and C finally deposit epitaxial SiC. The addition of chlorine (Cl) to the process has been thoroughly investigated due to its ability to reduce homogeneous nucleation in the gas phase attributed to the stronger Si-Cl bond compared to the Si-Si bond. In this thesis the fluorinated chemistry has been investigated, since the Si-F bond is even stronger than the Si-Cl bond and the fluorinated chemistry for SiC CVD has remained poorly understood. Using SiF4 as Si precursor in growth experiments combined with thermal equilibrium calculations of gas phase composition and quantum chemical computations of the surface chemistry first the silicon chemistry in the CVD process has been probed. It is shown that while growth rates on the order of 35 μm/h can be achieved with a fluorinated chemistry, the deposition chemistry is very sensitive to the mass flows of the precursors and not as robust as the chlorinated CVD chemistry which routinely yields 100 μm/h over wide conditions. By using the position for the onset of epitaxial growth along the gas flow direction as a new measurable, together with modeling, it is concluded that SiF is the main Si growth species with SiHF as a minor Si species contributing to growth. The carbon chemistry in a fluorinated SiC CVD process has been probed by a similar approach. Here it is found that the slow kinetics of the
منابع مشابه
بررسی تاثیر پارامترهای مختلف بر سینتیک رسوبدهی پوشش SiC اعمال شده به روش CVD بر روی کامپوزیت کربن - کربن
در این پژوهش پس از اعمال پوشش SiC به روش رسوبدهی شیمیایی فاز بخار (CVD) بر روی کامپوزیت کربن-کربن، به بررسی تاثیر پارامترهای مختلف بر سینتیک رسوبدهی پرداخته شده است. بهمنظور بررسی فازی پوشش SiC از آنالیز XRD، ریز ساختار کامپوزیت کربن-کربن قبل و پس از اعمال پوشش SiC از آنالیز SEM و بررسی فرآوردههای جانبی فرآیند از آنالیز EDS استفاده شده است. بر این اساس تاثیر پارامترهای دما، ترکیب گاز ورودی،...
متن کاملA Review of SiC Reactive Ion Etching in Fluorinated Plasmas
Research and development in semiconducting silicon carbide (SiC) technology has produced significant progress in the past five years in many areas: material (bulk and thin film) growth, device fabrication, and applications. A major factor in this rapid growth has been the development of SiC bulk crystals and the availability of crystalline substrates. Current leading applications for SiC device...
متن کاملHIGH RESOLUTION ELECTRON MICROSCOPY OF INTERFACES IN CVD -SiC
Interfaces in CVD 13-Sic have been analysed by high resolution electron microscopy. Models for the atomic structure of stacking faults, ~3 and c9 twins in 13 Sic structure have been derived from the geometric approach of coincidence grain boundaries and symmetry considerations. These models have been checked and compared to the experimental resuIts through high resolution image simuIation.
متن کاملEffect of Äo2 on Sic Volatilization Rate
Introduction: Our previous work on the volatilization rate of SiC in reducing gases [1, 2] was restricted to IW-2.8 and IW-6, oxygen fugacities (ÄO2Õs) 2.8 and 6 log units below the iron-wustite (IW) buffer. These data allowed us to estimate lifetimes of interstellar SiC grains (several months at 1200¡C) in a gas of solar composition (~IW-6). There is, however, evidence that ÄO2Õs for many comp...
متن کامل