Abstract
The deposition of in situ boron‐doped polysilicon from a mixture of diborane and silane was studied over a temperature range of 450°–600°C, and a diborane/silane flow ratio varying from 0.002 to 0.02. Diborane enhances the deposition rate and suppresses the activation energy of the deposition reaction. Diborane also reduces the temperature of the amorphous/polycrystalline transition. Resistivity after annealing (650° or 900°C) decreases with increasing diborane flow and with decreasing deposition temperature. Minimum resistivity is obtained by depositing the silicon as an amorphous film and annealing at high temperature (≥900°C). Of particular importance to low thermal budget processes, however, is the low resistivity (3.0 mΩ‐cm) obtained by annealing an initially amorphous film at 650°C.