IMPROVED PARTIAL VACUUM BORON DIFFUSION PROCESS.

摘要

A method is presented for the uniform and reproducible boron doping of many closely spaced silicon wafers in a single batch, wherein a particular process sequence and specified ranges of reactant gas compositions, flow rate and pressure are utilized. The method is illustrated for BCl3 as a boron source gas and H2 and O2 as an oxidant gas. Superior results are obtained when BCl3 and H2O are present in the reaction chamber at pressures less than 10 Torr (1.3 kPa) and molar ratios are in a specific range close to but not equal to that necessary for stoichiometric production of B2O3.