A Study on Photosensitivity Characteristics of Ba1-xSrxNbyTi1-yO3 Thin Film on SiO2/Si Substrate

Ba1-xSrxNbyTi1-yO3 thin film (45nm) deposited on a SiO2/Si substrate by the argon ionbeam sputtering technique is employed to fabricate planar thinfilms resistors used in the IC standard technology.The absorption spectra of the Ba1-xSrxNbyTi1-yO3 thin films, the photocurrent under different illumination and voltage, and the photocurrentfrequency characteristics of the filmresistors are studied.The experimental results show that Sr and Nb doped in BaTiO3 produce the impurity energy level in forbidden gap. Therefore,the energy gap drops down to 2.7eV and there are some consecutive absorption peaks in the visible region. The film has good photobehavior in the range from near ultraviolet to visible light, and it has high photosensitivity, high photoconductive gain and high linear illumination performance. While the illumination intensity is weak, the variaion of the current will be large, which is called onecenter recombination process; while the illuminaion is strong, the variation will be smooth and more linear, which is called twocenter recombination process.In this paper, the frequency response of the Ba1-xSrxNbyTi1-yO3 thinfilm resistor is investigated. The lifetime of optically excited carriers is 27ms at 200Lux.