ELECTRONIC PASSIVATION OF SILICON SURFACES BY HALOGENS

We report the electronic passivation of a silicon surface by iodine te rmination. The resulting surface recombination velocity on Si(100) is less than 1 cm/s which is better than that obtained in concentrated hy drofluoric acid (HF). We have produced a surface recombination velocit y of 20 cm/s using bromine. We present a simple model for these phenom ena of a surface coverage of Si-X where X is a monovalently bonded hal ogen atom. The effectiveness of the passivation by halogens is shown t o be limited by the oxidation of halogens by dissolved oxygen in solut ion. We demonstrate the use of halogen:methanol solutions as an altern ative to HF for the control of silicon surface chemistry.