Preparation Of Diamond Thin Film Pressure Sensor

At the time being, much effort has been made on the application of the semiconductor diamond thin film devices, and progresses have been made on its electronic application because the problem of doping art is well resolved. Now it has been confirmed that doped diamond thin film can be used as semiconductor device and can possibly serve as a new generation of semiconductor material to replace silicon, and it can be prepared to be sensor devices with high reliability, high temperature-resistance and radiation-resistance for its excellent properties. After the success of temperature and pressure sensor in America, the practicality of diamond film are now focusing on high reliability and sensitivity at high temperature, erosion and radiation. This is the breakthrough of the soaring of the diamond thin film based functional devices now.The pressure - resistance mechanism of the B doped diamond thin film is discussed from the assorted effective factors of the conductance of semiconductor, combining with the band theory of semiconductor, theory of deforming potentiality, valence band splitting model and polymer-crystal model of Mayadas-Shatzkes.The preparation of diamond thin film pressure sensor CMOS chip:Make use of the "non-sub crystal and non-deflective voltage quasi-single crystal deposition" method mentioned in this article, the even pure-diamond thin film with 20-30 um is deposited on the polished silicon substrate by the hot-fuse CVD method. After the erosion of the silicon substrate, the interface of diamond and silicon is required to be smooth and even without polishing. This is very important to obtain even stress bear upon the film.On the even and smooth pure diamond, the covered filmed optional growing technology is used to direction-fixed deposit four B-doped diamond resistances forming Wheatstone bridge to prepare the self-compensated pressure sensor chip.The creative points:Experimental aspects: 1. non-sub crystal and non-deflective voltage quasi-single crystal deposition" method is put forward. Depositing dense and smooth diamond film and B-doped diamond resistance on the smooth silicon substrate were probed to make even distribution of stress and to enhance the stability of the pressure sensor. This has not been reported yet (the patent has been applied). 2. The solution of hydrofluoric acid and nitric acid is used to erode silicon' shape. We can predigest experimentation by this way.The item is supported by the National "863" plan (863-715-002-0060), Key foundation of national education department (00134) and key item of Tianjin nature science foundation (003800211)...