Properties of low‐pressure chemical vapor deposited dielectric films from hexamethyldisilazane

Hexamethyldisilazene (HMDS) is shown to be an effective single‐source reactant of Si, C, and N for electronic thin films deposited using low‐pressure chemical vapor deposition (LPCVD). Pyrolytic deposition, at 800 °C, in the absence of oxidants yielded silicon carbide–nitride films which are insoluble in buffered HF. These films have a refractive index of 2.3 to 2.5 and an infrared absorption maximum at 804 cm−1. Controlled addition of oxygen to HMDS yielded silicon carbide–oxynitride films which are etchable with buffered HF. These films have a refractive index of 1.45 to 2.0 and are an effective diffusion barrier for phosphorus. Complete oxidation forms films of SiO2 with a refractive index of 1.41 and an infrared absorption maximum at 1060 cm−1. Auger electron spectrometry, secondary ion mass spectrometry profile analysis, ellipsometry, and Fourier transform infrared spectrometry were used to study the chemical composition of the films as a function of LPCVD parameters.