| 摘要 |
PURPOSE:To perform an effective diffusion with a steep gradient and a little neutral impurities by a method wherein single crystal is preheated at a temperature slightly lower than that of impurity diffusion and a heat diffusion is performed on the impurities located at a prescribed small spot by irradiating a laser beam. CONSTITUTION:A compound semiconductor crystal 6 is sealed in an evacuated and closed-quartz tube 7 together with the impurities and a proper quantity of negative elements 8 as an ingredient, and they are heated at the temperature a little lower than that at which a diffusion is performed in a heating furnace 9. Then, by irradiating the laser beam 5 on a limited small region on the surface of the crystal 6, the heated lower section along of this small region is heated at a temperature of 900 deg.C or above and a limited impurity diffusion is performed. A controlling device 11 controls movements of a shifting device 10 in order to easily select an optical minute spot, and the device 11 also controls a modulator 3 so that a required pattern, a diffusion pattern and a diffusion profile are formed in crystals by an oscillation beam 2 of a high output laser 1. |
