Sharp phosphorus spikes in silicon grown by fast gashyphen;switching chemical vapor deposition at reduced and atmospheric pressure

摘要

Sharp phosphorus doping spikes in silicon were grown by fasthyphen;gashyphen;switching chemical vapor deposition at temperatures between 800 and 850thinsp;deg;C using disilane and phosphine in 0.03, 0.1, and 1 atm hydrogen carrier gas. The phosphine doping gas was added while growing silicon at a rate of 0.15ndash;0.5 nm/s. High depth resolution secondary ion mass spectrometry measurements have revealed sharp and high concentration dopant profiles. Peak phosphorus concentrations up to 7times;1019cmminus;3and a full width at half maximum of 7 nm were obtained. Electrical measurements show that at these concentrations about 40percnt; of the dopant atoms is electrically active in structures grown at 1 atm. Formation of doping tails is shown to be suppressed at atmospheric hydrogen pressure.