A NOVEL REACTOR DESIGN CONFIGURATION FOR CONTAMINATION CONTROL AND IMPROVED PERFORMANCE IN THE POLYSILICON DOPING PROCESS USING POCL3

Conventional POCl3 reactors have process limitations because of the ha zardous nature of process by-products. Experiments were conducted usin g a novel design quartz flange and stainless steel clamp exhaust confi guration, along with a scavenger insulation block, which eliminated pr ocess by-product buildup inside the reactor tube in the scavenger area . Experiments included variations in doping temperature, process time, POCl3 flow rate, and carrier and exhaust gas flow rates. This novel(e ) hardware design practically eliminates by-product condensation and d ripping outside the reactor, which reduces cross-contamination and sta inless steel corrosion problems and prevents potential minority carrie r lifetime degradation. Equipment downtime is significantly reduced by eliminating autodoping and the need for frequent process tube steam c leans. Run capability is extended because of the new design, which als o provides superior exhaust control and safer operation. The design al so allows doubling of the number of wafers processed with improved she et resistance uniformity. Regression equations were obtained for calcu lating sheet resistance, which can be a viable tool for process engine ers. The new reactor configuration provides significant advantages in reduced equipment downtime, increased savings in material, and improve d process performance.