ELECTRONIC PASSIVATION OF SILICON SURFACES BY HALOGENS

We report the electronic passivation of a silicon surface by iodine termination. The resulting surface recombination velocity on Si(100) is less than 1 cm/s which is better than that obtained in concentrated hydrofluoric acid (HF). We have produced a surface recombination velocity of 20 cm/s using bromine. We present a simple model for these phenomena of a surface coverage of Si-X where X is a monovalently bonded halogen atom. The effectiveness of the passivation by halogens is shown to be limited by the oxidation of halogens by dissolved oxygen in solution. We demonstrate the use of halogen:methanol solutions as an alternative to HF for the control of silicon surface chemistry.