The properties of LPcvd Si/sub 3/N/sub 4//SiO/sub 2/ film electret based on silicon

By means of the technology of LPcvd and thermal oxidation the Si/sub 3/N/sub 4//SiO/sub 2/ double-layer electret film was prepared on different doped silicon wafers. The experimental results show that the Si/sub 3/N/sub 4//SiO/sub 2/ double-layer film possesses a good storage ability of negative charges after modifying the surface with HMDS, and all of the charges were almost trapped in the bulk of upper layer Si/sub 3/N/sub 4/ film. In addition, the TSD spectra of Si/sub 3/N/sub 4//SiO/sub 2/ film were influenced greatly by the differences of the dopants in the silicon wafers.