| 摘要 |
PURPOSE:To improve the distribution in a plane of the thickness of an epitaxial layer at the fabrication of the semiconductor laser element of a buried hetero structure by performing liquid-phase epitaxy with using the substrate in which each of the angles among those made by the surface of the single crystal substrate with a crystallographically main plane, which are in parallel and vertical directions to the direction of a stripe-form mesa are present within the specified range. CONSTITUTION:If the angle theta1 in a vertical direction to the direction of a stripe-form mesa is large, the formed mesa becomes unsymmetrical and has a bad influence upon the element characteristics. A permissible range of theta1 is as 0<=theta1 <=10. Meanwhile, the angle theta2 in a parallel direction to the direction of the stripe-form mesa can be relatively large in respect of the uniforming of distribution in a plane of the epitaxial layer. However, the reflectance of the laser light reflected by a mirror surface of the element declines as the difference from 90 deg. of the angle made by the mirror surface of the element formed on a cleavage plane with the projecting direction of the laser light in the element becomes larger. The reflectance of the laser light is required to be 80% or over and the upper limit of theta2 determined according to the above value is 2 degree and the lower limit, which is determined by the degree of effect upon uniforming of the thickness of the epitaxial layer, is as 0.5 degree <=theta2 in order to attain 0.1mum or under by sigma value. |
