Development of low temperature PECVD nitride with low stress and low etch rate in BOE solution for MEMS applications

This paper presents the development of a low temperature silicon nitride deposition process using plasma enhanced chemical vapor deposition (PECVD) system. The nitride films showed low stresses ranging from compressive to tensile and very low etch rates in the buffered oxide etch (BOE) solution. These nitride films can be used as MEMS structure materials where suspended structures are involved:In this work, individual process parameters such as SiH₄/H₂/N₂ gas flows, chamber pressures, temperatures and HF powers that related to the nitride film stress and etch rate in BOE solution are also investigated.