LIQUID PHASE EPITAXIAL GROWTH METHOD

PURPOSE:To grow layers without deforming a groove by successively laminating the 1st layer of GaAlAs and the 2nd layer of GaAs on a GaAs substrate, forming a stepped groove that reaches the substrate from the surface of the 2nd layer, and coating the surface of the substrate with a melt for growth having a specified degree of super-saturation. CONSTITUTION:The 1st layer 12 of n-type GaAlAs and the 2nd layer 13 of n-type GaAs are successively laminated on a p-type GaAs substrate 11 [figure (a)]. A groove 14 that reaches the substrate 11 from the surface of the 2nd layer 13 is formed with an etching soln. consisting of H2SO4, H2O2 and water in 3:1:1 ratio [figure (b)]. The cross-section of the groove 14 is an inverted triangle. The 2nd groove 15 having a larger width W of opening than the groove 14 if formed with an etching soln. cont. NH4OH and H2O2 in 20:1 ratio [figure (c)]. The cross-section of the groove 15 is an inverted trapezoid. The 1st clad layer 16 of p-type GaAlAs is grown on the surface of the 2nd layer 13 by liq. phase epitaxial growth [figure (d)]. An active layer 17 of undoped GaAlAs, the 2nd clad layer 18 of n-type GaAlAs and a cap layer 19 of n-type GaAs are successively grown on the layer 16 by epitaxial growth [figure (e)].