Low Temperature Thermal Chemical Vapor Deposition of Silicon Nitride Thin Films for Microelectronics Applications

Silicon nitride technology has been incorporated in ultra-large scale integration (ULSI) microchip fabrication, thin film transistors (TFT), solar cells, and many other applications in a rapidly expanding market. Nevertheless, silicon nitride technologies currently in use face considerable limitations. Low pressure chemical vapor deposition (LPCVD) occurs at relatively high temperature (>700 °C) and plasma enhanced chemical vapor deposition (PECVD), although occurring at temperatures below 300 °C, produces hydrogen-rich films and could be self-limiting in terms of conformality and damage to the devices due to ion bombardment. In the present work, successful low temperature thermal chemical vapor deposition (LTCVD) of silicon nitride is reported on 8” silicon wafers. The use of a halide-based silicon precursor, tetraiodosilane (SiI4) has led to the deposition of high quality silicon nitride thin films at temperatures as low as 300 °C.Characterization of resulting film properties has been performed to determine their dependence on deposition parameters by Auger Electron Spectroscopy (AES), Rutherford Backscattering Spectroscopy (RBS), Fourier Transform Infrared (FTIR), Nuclear Reaction Analysis (NRA), Ellipsometry, Capacitance-Voltage (C-V), and Current-Voltage (I-V) measurements.