| 摘要 |
PURPOSE:To alleviate internal stress yielded at an interface between a dielectric film at an end surface and a laser element, in a semiconductor light emitting device, in which the dielectric film is formed at each end surface, by changing the refractive index of the dielectric film at the end surface in the direction of the thickness of the film. CONSTITUTION:An SiN (refractive index n1=1.49) film is formed to a thickness of an optical film thickness lambda/2 as a dielectric film 4 having distribution in refractive index at each end surface of a laser layer 1. The SiN film is formed by an ordinary chemical vapor growth (CVD) method as follows: a ratio between silane (SiN4) and ammonia (NH3) as raw material gases is adjusted; composition is controlled; the refractive index (n) becomes no=3.34 when the film thickness is 0; the refractive index is gradually decreased with the increase in film thick ness; g and the refractive index (n) becomes n1=1.91 when the film thickness is lambda/2. When a protecting film such as this is formed, difference in strain be tween a cleavage surface and the SiN film becomes less. Even in heat treatment, occurrence of cracks and bubbles can be suppressed. |
