Semiconductor laser with improved oscillation wavelength reproducibility

• US 5,345,463 A
• Filed: 04/13/1993
• Issued: 09/06/1994
• Est. Priority Date: 04/14/1992
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Ohnaka, Kiyoshi, Mannoh, Masaya
• Primary Examiner(s): Davie, James W.
• Application Number:
  US08/045,423
• Time in Patent Office: 511 Days
• Field of Search: 372/45, 372/46, 372/44
• US Class Current: 372/45.012
• CPC Class Codes: H01S 5/2231 with inner confining structure only between the active layer and the upper electrode
• CPC Class Codes: H01S 5/305 characterised by the doping materials used in the laser structure
• CPC Class Codes: H01S 5/3211 characterised by special cladding layers, e.g. details on band-discontinuities
• CPC Class Codes: H01S 5/32325 red laser based on InGaP

Abstract

A lateral mode control type of semiconductor laser has a high-yield structure having a long life and improved oscillation wavelength reproducibility. A diffusion limit layer formed of an undoped Ga₀.5 In₀.5 P layer and an undoped (Al₀.6 Ga₀.4)₀.5 In₀.5 P layer is provided between a p-(Al₀.6 Ga₀.4)₀.5 In₀.5 P clad layer and an undoped Ga₀.5 In₀.5 P active layer. The diffusion limit layer has a diffusion coefficient smaller than that of the clad layer. Impurity Zn diffused from the p-(Al₀.6 Ga₀.4)₀.5 In₀.5 P clad layer during crystal growth or working is trapped in the undoped Ga₀.5 In₀.5 P layer almost entirely. A part of the impurity Zn diffuses in the undoped (Al₀.6 Ga₀.4)₀.5 In₀.5 P layer thereunder but does not reach the undoped Ga₀.5 In₀.5 P active layer.

Claims

1. A semiconductor laser having a double hetero structure, comprising:

a GaAs substrate;

a first lattice-adjusted (Al_X Ga_1-X)InP clad layer formed on the substrate;

an (Al_Y Ga_1-Y)InP active layer formed on the first lattice-adjusted clad layer with (0≦

Y<

X≦

1);

a second lattice-adjusted (Al_X Ga_1-X)InP clad layer formed on the active layer; and

a low-doped (Al_Z Ga_1-Z)InP layer interposed between the active layer and at least one of the clad layers with 0≦

Y<

Z≦

1, a carrier concentration in the low-doped layer being less than a carrier concentration in either of the first and second clad layers.

2. A semiconductor laser having a double hetero structure, comprising:

a GaAs substrate;

a first lattice-adjusted (Al_X Ga_1-X)InP clad layer formed on the substrate;

an (Al_Y Ga_1-Y)InP active layer formed on the first lattice-adjusted clad layer with (0≦

Y<

X≦

1);

a second lattice-adjusted (Al_X Ga_1-X)InP clad layer formed on the active layer; and

a multi-layer diffusion limit layer interposed between the active layer and at least one of the clad layers, the multi-layer diffusion limit layer being formed from a plurality of sub-layers of (Al_a Ga_1-a)InP, (Al_b Ga_1-b)InP, . . . , (Al_n Ga_1-n)InP with a<

b<

. . . <

n, each of the sub-layers having a thickness not greater than 10 nm, at least one of the sub-layers having an impurity diffusion coefficient which is less than an impurity diffusion coefficient of either of the clad layers.