Properties of furnace crystallized polysilicon films prepared by rf sputtering

We have investigated the materials and electrical properties of furnace crystallized polysilicon films prepared by r.f. magnetron sputtering under different deposition pressure and annealing temperatures. Rutherford backscattering spectroscopy, Auger electron spectroscopy, X-ray diffraction and transmission electron microscopy were used to analyse the microstructure, and temperature dependence of the dark conductivity was used to characterize the trap state density in the grain boundaries. Our results show that the sputtering pressure is an important parameter affecting the argon and oxygen impurities in the film. The grain size decreases at higher sputtering pressure. There is an optimum pressure at which maximum Hall mobility and minimum trap state density are obtained. Above 1 100 degrees C a recrystallization grain growth process occurs, resulting in larger grain size and a rapid increase in Hall mobility.