| 摘要 |
PURPOSE: A method of exposing the majority of the edges, especially those with the highest Al-bearing layers, is provided to leave the remaining layers intact and connected in wafer processing. CONSTITUTION: For AlGaAs LEDs the confining layers adjoining the active layer possess the highest Al composition. From failure analysis of non-passivated, WHTOL-aged, AlGaAs LEDs, it was discovered that corrosion occurs the fastest at the exposed surfaces of the high Al-content confining layers. By placing a high-quality native oxide at the exposed surfaces of the high Al-content confining layers which protect from the formation of the 'poor' oxide, it is possible for LEDs to retain essentially their same light output after 2,000 hours of WHTOL testing. Further, it is possible to improve carrier confinement, carrier injection, wave guiding, and other properties by increasing the Al-content of different layers.
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