Identification of Film-Forming Species during SiC-CVD of CH3SiCl3/H2 by Exploiting Deep Microtrenches

The surface reaction kinetics of chemical vapor deposition (CVD) of silicon carbide (SiC) from methyltrichlorosilane (MTS; CH3SiCl3) and hydrogen were studied to identify gaseous species contributing to SiC film formation. First, SiC was deposited into relatively deep microtrenches with aspect ratios of up to 64: 1, and the film-thickness profiles within the deep microtrenches were analyzed to evaluate the sticking probabilities (eta) of the film-forming species. Two film-forming species were identified with eta of 10(-2) and 10(-5) at 1,000 degrees C. Next, their partial pressures at several positions in the reactor were estimated from their respective. and deposition rates. The low-eta species was identified as MTS by comparing the partial pressure measured by quadrupole mass spectrometer with that calculated by elementary reaction simulations. Similarly, the high-eta species was likely CH2SiCl3 generated via gas-phase decomposition of MTS. Such identification is crucial to optimize the deposition conditions and also design of a reactor. (c) 2019 The Electrochemical Society.