Silicon nitride, a new diffusion mask

Although in the last decade silicon dioxide has been used extensively as a diffusion mask in semiconductor device fabrication, it has many limitations. It fails to mask many important diffusants such as gallium, aluminum, zinc, and oxygen. The masking properties of silicon nitride have been investigated. The results show that silicon nitride masks not only the same diffusants as silicon dioxide but also many diffusants where silicon dioxide fails.