DIFFUSION OF PHOSPHORUS INTO SILICON USING PHOSPHINE GAS AS A SOURCE.

Diffusion experiments were conducted using a gaseous dopant (PH//3) into silicon in an open tube system. The findings of these experiments with respect to resistivity and diffusion depth are presented for different gas velocities, temperatures of diffusion and diffusion times. It is possible to achieve reproducable rho //s of 15 ohms per square with acceptable tolerance limits ( plus or minus 5%) with proper choice of the gas flow parameter and a suitable program cycle. The process yields a higher concentration gradient at the p-n junction than other diffusion methods used for phosphorous diffusion. This process is, therefore, best suitable for emitter diffusion of switching transistors.