Method for preparing high-temperature pressure sensor chip

The invention belongs to the technical field of micro sensors and relates to a method for preparing a high-temperature pressure sensor chip. The method, by using silicon-silicon bonding techniques twice, connects a piezoresistive layer with a pressure sensitive film, and connects the pressure sensitive film and substrate silicon respectively to form an integral body. The piezoresistive layer is prepared by a high-temperature boron diffusion doping method, and is separated from the pressure sensitive film by an oxide insulating layer. The method of the invention uses the boron diffusion assisted bonding mode to realize reliable bonding of the piezoresistive layer and the pressure sensitive film while preparing the piezoresistive. Further, , a possibility caused by preparing a conventional high-temperature pressure sensor directly by using SOI sheet diffusion is avoided that the leakage current increases due to the entry of boron atoms into an oxide layer and deteriorates the stability.Thus, the high stability