| 摘要 |
PURPOSE:To lessen the current of a threshold value, and moreover to realize the titled diode with current-optical output characteristics, by which the diode can go so far as to favorably output higher photo output, by a method wherein a first conductive-type impurity diffusion region is formed at the common prescribed position of a second clad layer and an optical waveguide layer in such a way that its diffusion tip doesn't reach an active layer. CONSTITUTION:When inpurities are added to a GaAlAs layer in high concentration, its forbidden band width becomes narrower by a band tail effect. For example, in a Ga0.8Al0.2As layer, the forbidden band width of its P type high-concentration impurity diffusion region becomes narrower by 0.04-0.08eV, compared to the forbidden band width of its non-diffusion region. As a result, the forbidden band width of an optical waveguide layer 8 (an N type Ga0.81Al0.19As layer), which is a non-diffusion region, is wider by about 0.4eV, compared with the forbidden band width of an acive layer 3, but the forbidden band width of the part of a P type impurity diffusion region 9 consisting of a P type Ga0.81Al0.19As layer, wherein P type impurities of 10<19>-10<20>/cm<3> have been diffused, becomes equal with the forbidden band witdth of the active layer 3 or becomes narrower than that of the active layer 3. Accordingly, the part of the P type impurity diffusion region 9 consisting of the P type Ga0.81Al0.19As layer functions as an absorption region of laser beams, which generates at a luminous region (a), and light in the parallel direction to the active layer 3 is confined under the luminous region (a), where the P type impurity diffusion region 9 has not been formed. |
