Low temperature photo-CVD oxide processing for semiconductor device applications

A low temperature (50-300°C) process for the photochemical vapor deposition (Photo-CVD) of a variety of oxide dielectrics has been developed by Hughes Aircraft Company. The low pressure Photo-CVD oxide process (PHOTOX^TM) relies solely on the selective absorption of photonic energy for initiation in contrast to thermal and plasma excitation techniques commonly employed in the industry today. The PHOTOX silicon dioxide (i.e. SiO2formed by the PHOTOX process) dielectric depbsited at 200°C with a refractive index of 1.46 is stoichiometric SiO2with a breakdown strength of 6.0×10⁶V/cm. The PHOTOX process provides exceptional step coverage and is capable of producing virtually pinhole-free (<2/cm²) dielectrics with uniform surface morphology. The electrical interface associated with the PHOTOX SiO2has been examined on a number of elemental and compound semiconductors including silicon and indium phosphide which reveal distinct advantages of the process compared to thermal and plasma CVD processes.