Rate constants for the etching of intrinsic and doped polycrystalline silicon by bromine atoms

The rate constants for the reaction of bromine atoms with intrinsic and heavily doped n+-type polycrystalline silicon, as well as their temperature dependencies, are reported for the first time. The rate constant for intrinsic silicon is given as k=(4±2)×107 nm min−1 Torr−1e−(62±2kJ/mol)/RT and for n+-type silicon with a phosphorus number density of 5×1018 cm−3, k=(1±1)×1011 nm min−1 Torr−1e−(62±2kJ/mol)/RT. Although the etch rates for the n+-type silicon are 2–3 orders of magnitude larger than for intrinsic silicon at the same temperature and atom concentration, the difference in the two rate constants is due to a change in the pre-exponential Arrhenius factor and not in the activation energy.