Characterisation of deformations and texture defects on polished wafers of III-V compound crystals by the magic mirror method

Abstract

The technique based on the concept of the ancient Chinese holy brass mirror, the magic mirror or 'Makyoh', is utilised to inspect and characterise the surfaces of polished GaAs wafers. This non-destructive method was first introduced to examine the polished surfaces of silicon wafers and epitaxial layers. Undulations and latent damage on the mirror-like polished surfaces are easily visualised over the entire substrate in real time. Thus study extends the magic mirror method to inspect III-V compound crystals, Some polished GaAs, GaP and InP wafers are examined and discussed. Saw marks, dimples, polish scratches, texture defects and other damage, e.g. twin lines, facet boundaries and striations, hidden in the polished surface are observed over the entire wafer. Comparison between etched wafers and unetched wafers observed by the magic mirror and revealing similar deformations is discussed.