Structural modification in reactive-ion-etched i-InP and n+-InP studied by Raman scattering

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Abstract
Structural and electrical property modifications in i‐InP and n+‐InP by reactive ion etching have been characterized by using Raman scattering to observe changes in the positions and intensities of intrinsic phonons and coupled phonon‐plasmon bands. Different etch gas compositions (Ar, He, CH4/H2, CH4/Ar, CH4/He, and CH4/H2/Ar), bias potentials (0–500 V), and etch times were examined. Electrical property changes were followed by correlating results with a one‐sided abrupt junction model. Ar and He, which interact with the material by physical sputtering processes, were found to induce the greatest structural and electrical modifications. Ar‐etched samples exhibited the greatest structural modification, with evidence of structural damage coming from far beyond the calculated penetration depth of low‐energy Ar+, while samples etched in methane‐based plasmas showed very little structural perturbation. Etching in all of the gas mixtures used produced some degree of electrical modification in n+‐InP, with He plasmas causing the most significant changes. In general, samples etched with lower ion energies and sputter components exhibited the least structural and electrical modification.