AbstractThe formation of rugged surface polycrystalline silicon (poly-Si) using Cl2/O2 plasmas in which O2 concentration is 0-10 % has been investigated. Phosphorus doped poly-Si (n+ poly-Si) surface is rugged by the plasma etching under the condition that O2 concentration are 1-5 % at 10 Pa, but is not rugged at 1.3 Pa. On the other hand, undoped poly-Si surface is not rugged in Cl2 /0-10 %O2 plasmas at 10 Pa. Oxygen and phosphorus play an important role in the ruggedness of n+ poly-Si. The ruggedness mechanism has been investigated using scanning electron microscope, optical emission spectroscopy and mass spectrometry. The ruggedness mechanism is suggested that in Cl2 plasmas added a small amount of oxygen, n+ poly-Si is etched selectively at the grain boundaries which contain more phosphorus than in grains. The Cl emission intensity and n+ poly-Si etch rate reach maximum in Cl2/3 %O2 plasma at 1.3 Pa. Oxygen has a possibility of promoting SiCIx dissociation and increasing Cl radicals.
Optical emission spectroscopy for plasma diagnosis of 2.45 GHz ECR ion source at Peking University
