| 摘要 |
<p>It has been noticed that the patterns produced by photoetching are subject to pattern broadening where the results are not as sharp as expected. It has now been realised that this is partially caused by the diffussion of the active species away from the region where they were created. To reduce this pattern broadening, the substrate is protected by a fugitive coating which is removed by the illumination. Native oxide coatings are particularly suitable for InGaAsP substrates. These are conveniently applied by exposing to substrate to 20⁰/o O₂ + 80⁰/oN₂ for about 3 minutes at 450⁰C.</p> |
