| 摘要 |
PURPOSE:To enable to form grooves or diffusion regions of different depths on the same substrate at the same time according to etching or a diffusion process of one time by a method wherein a diffusion rate-determining etching liquid is used, and sizes of opening parts for etching are made to differ. CONSTITUTION:A clad layer 2-1, an active layer 3, a clad layer 2-2, a second active layer 4 and a clad layer 2-3 are grown on an InP substrate 1. A CVD-SiO2 film is grown thereon, and opening parts of a 2.5mum width stripe type and a 5mum width stripe type are formed. When etching is performed according to a Br2-CH3OH liquid, a groove of 2.2mum etching depth is obtained at the 2.5mum stripe part, and a groove of 1.0mum etching depth is obtained at the 5mum stripe part. Then, when diffusion of Zn is performed as to obtain 2.0mum diffusion depth, the diffusion base of a region 8 reaches the first active layer 3 at the 2.5mum stripe part, and the diffusion base of a region 9 reaches the second active layer 4 at the 5mum stripe part. |
