Anisotropic Etching of Heavily Doped Polysilicon by a Hot Cl 2 Molecular Beam

Anisotropic etching of n+ poly-Si is achieved using a hot Cl 2 molecular beam and a sidewall protection technique. A hot molecular beam is produced by a free jet expansion of a gas heated in a furnace. A nitrogen radical beam is used to prevent the sidewall etching. The etch rate of n+ poly-Si is 4.3 nm/min at the anisotropic etching condition.