SURFACE STUDIES OF THE INTERACTION OF CL-2 WITH INP(100)(4X2) - AN INVESTIGATION OF ADSORPTION, THERMAL ETCHING AND ION-BEAM ASSISTED PROCESSES

The reactions of chlorine on the InP(100)(4 × 2) surface have been investigated using LEED, AES and TDS techniques. Chlorine forms a strongly bound chemisorbed monolayer on the semiconductor surface during low gas exposures. At high gas exposures, bulk corrosion sets in and an In-rich chloride film is formed at the interface which desorbs as InCl3. The degree of surface segregation which takes place is found to depend on the chlorine dosing pressures employed and the chemistry exhibited is also very sensitive to the state of the semiconductor surface; on In enriched interfaces corrosion takes place some 300 times more rapidly and InCl rather than InCl3 is the desorbing product. The surface transformations brought about by low energy ion beams are investigated. Ion beam irradiation sputters InCl and P4 from the chloride layer and converts the chloride rich corrosion scale into InCl. A mechanism for ion beam assisted etching is proposed and the results compared to previous studies. © 1990 Elsevier Science Publishers B.V. (North-Holland).