| 摘要 |
PURPOSE:To improve productivity and output characteristic, by applying Fecl3 etching with a resist mask so as to shape a light takeout surface into a very small lens when a surface LED in homojunction of InP or in heterojunction with InGaAs is prepared. CONSTITUTION:On a substrate 8 having an InP/InGaAsP double hetero-structure, electrodes 7 of an n type region are formed with holes of 150mum in diameter opened, while electrodes 9 of a p type region are attached onto the back surface of the substrate. The substrate thus prepared is inserted with the electrodes 7 up into a glass vessel 12 filled up with an FeCl3 solution (35+ or -1% dense) 11, and a light is applied thereon with uniform luminance. Consequently, only the substrate 8 is etched, InP is removed vertically by etching, the depth of etching is proportional to a time if exposure constant, and a great number of microlenses 2n are formed on the surface. Therefore, the take-out efficiency of LED, as well as the connection efficiency with optical fibers, is improved. According to this constitution, productivity is becomes excellent owing to a simple device and a processing requiring only a short time, and LED having an improved optical output characteristic and a long wavelength band can be obtained. |
