Preparation Of LaP₅O₁₄ Powder By Sol-gel And Development Of Phosphorus Diffusion Source Chips

Solid-state phosphorus diffusion source for doping silicon wafer was a functional material which was flaky,stable at room temperature,and it can be decomposed and stablely released P2O5 at high temperature. In this artile, Solid phosphorus diffusion source chips were produced by sintering method using LaP5O14 powder as materials which was prepared by sol-gel process. The samples were characterized and analyzed by DSC-TG,DTA-TG,XPD,SEM.The results shows:The LaP5O14 power can be obtained by calcinateing the gelatinate at 800℃for 5 hours, and the obtained LaP5O14 is about 10μm in length. P2O5 can be released from the LaP5O14 powder with constant rate at 850℃, and there was a good linear relationship between the weight loss of the powder and the heat preservation time, the percent of the powder'weight loss at 850℃for 5h was proportional to the content of LaP5O14. With the calcinateing temperature increasing,the content and the grain size of LaP5O14 was increased and then decreased. Along with the holding time growing, the content and the grain size of LaP5O14 was increased.The chips were produced by liquid state sintering using LaP5O14 powder,at 900℃for 1h,adding 6% phosphorus glasses as aids. As the growth of sintering temperature,the content of LaP5O14 was decreased,the gas porosity was increased and then decreased, the grain size and the density were decreased and then increased;Along with the holding time increasing, the content of LaP5O14 and the density were decreased, the grain size was increased. But with adding number of phosphorus glasses, the gas porosity and the sofening temperature were decreased,the density was increased and then decreased.