Doping of p-type shallow junctions using electron beam evaporation of boron layers for compatibility with complementary-metal-oxide-semiconductor technology

摘要

Electron-beam evaporation was used as a low-temperature deposition process of boron and boron/amorphous-silicon layers as dopant sources in rapid thermal diffusion. High efficiency of doping is attributed to high dopant supply from the boron layer to the silicon substrate. Oxygen ambient leads to layer consumption and thus opens possibility for the source removal after diffusion. Dopant activation results in high carrier concentration within the junctions. High concentrations of dopant cause generation of precipitates at the B/Si substrate interface but not at the B/Si cap interface. The process is compatible with the complementary-metal-oxide-semiconductor technology since the low temperature of the source deposition facilitates masking of the dopant by a patterned photoresist and its subsequent lift-off removal from the silicon surface.