1. Field of the Invention
This invention relates to a semiconductor light generating device for the generation of ultraviolet light and so on, and relates to a method of making the ultraviolet light generating semiconductor device.
2. Related Background Art
Publication 1 (Jpn. J. Appl. Phys. Vol. 41 pp. L1434-1436) and Publication 2 (50th Conference of Japan Society of Applied Physics, Extended Abstract, pp. 431) disclose semiconductor light generating devices. These semiconductor light generating devices include a Cu—W substrate and a semiconductor structure for light emitting diodes (LEDs). This light emitting diode semiconductor structure has an active layer of an InGaN multiple quantum structure. A Au—Sn layer is formed on the Cu—W substrate. The active layer in the light emitting diode semiconductor structure is provided between a p-electrode for p-type semiconductor and an n-electrode for n-type semiconductor. The semiconductor light generating devices are fabricated in the following steps. A GaN buffer layer and a semiconductor structure for the light emitting diode are sequentially formed on a sapphire substrate by an MOVPE or ELO method. The p-electrode is evaporated on one side of the light emitting diode semiconductor structure and the p-electrode is bonded to the Cu—W substrate using Au—Sn solder. The sapphire substrate is removed by a laser lift-off (LLO) method using KrF excimer laser, and the remaining GaN buffer layer is removed by polishing it with a chemical mechanical polishing (CMP) method. The n-electrode is formed on the polished surface to form the semiconductor light generating devices.