PURPOSE: To diffuse Zn selectively only into a prescribed part of the impurity diffusion region.
CONSTITUTION: Approximately 3 μm-thickness n-type Al0.3Ga0.7 layer 11, approximately 0.2 μm-thickness n-type GaAs active layer 12, approximately 2 μm-thickness P-type Al03Ga0.7As layer 13 and approximately 1 μm-thickness n-type GaAs layer 14 are grown on n-type GaAs substrate 10 by the liquid phase growing method. Zn 16 is diffused at 600°C through 15 μm-width and 250 μm-interval stripes which are opened in SiO2 film 15, which is caused to adhere onto the fourth layer, in the direction vertical to the cleavage plane by the photo resistor technique, and diffusion front 17 is controlled in the halfway position of the third layer. Next, SiO2 film 15 is removed; and after a SiO2 film as a dielectric film is caused to adhere onto all the surface with a thickness of 3000, a SiO2 stripe-shaped film is formed across the stripe. This wafer is sealed in a quartz ampul in a vaccum degree below 10-6Torr and is subjected to heat treatment for three hours in the furnace at 750°C, so that Zn in the part except the SiO2 film is diffused rapidly and the front reaches the first layer.
NISHIDA KATSUHIKO
RANGU ROI
