Annealing characteristics of boron- and phosphorus-implanted polycrystalline silicon

Polycrystalline silicon films implanted with 1×1012 to 7.8×1015/cm2 doses of boron and phosphorus were isochronally annealed up to 1100 °C. Annealing below 600 °C removes the radiation damage created by the implantation process. For doses higher than 1×1014/cm2 an abrupt decrease in sheet resistance takes place between 650 and 700 °C. Hall measurements show that this decrease is the result of a large increase in both the carrier concentration and mobility. Electron-reflection diffraction patterns show that recrystallization takes place within this temperature range. Annealing above 700 °C only causes a small further decrease in the sheet resistance.