Strained quantum well structure

• US 5,671,242 A
• Filed: 08/16/1995
• Issued: 09/23/1997
• Est. Priority Date: 09/02/1994
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Takiguchi, Tohru, Goto, Katsuhiko
• Primary Examiner(s): Bovernick, Rodney B.
• Assistant Examiner(s): LEUNG, QUYEN PHAN
• Application Number:
  US08/515,909
• Time in Patent Office: 769 Days
• Field of Search: 372/45, 372/46, 257/18
• US Class Current: 372/45.011
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G02F 1/01708 in an optical wavequide structure
• CPC Class Codes: G02F 1/01766 Strained superlattice devices; Strained quantum well devices
• CPC Class Codes: H01S 5/0265 Intensity modulators intra-cavity modulators H01S5/0625
• CPC Class Codes: H01S 5/2272 grown by a mask induced selective growth
• CPC Class Codes: H01S 5/2275 mesa created by etching
• CPC Class Codes: H01S 5/34 comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers H01S5/36 takes precedence
• CPC Class Codes: H01S 5/3403 having a strained layer structure in which the strain performs a special function, e.g. general strain effects, strain versus polarisation
• CPC Class Codes: H01S 5/3406 including strain compensation
• CPC Class Codes: H01S 5/34306 emitting light at a wavelength longer than 1000nm, e.g. InP based 1300 and 1500nm lasers
• CPC Class Codes: H01S 5/34313 with a well layer having only As as V-compound, e.g. AlGaAs, InGaAs
• CPC Class Codes: H01S 5/3434 with a well layer comprising at least both As and P as V-compounds

Abstract

A semiconductor device includes a substrate having a lattice constant and a stress compensation strained quantum well layer including compressively strained layers having a lattice constant larger than the lattice constant of the substrate and tensively strained layers having a lattice constant smaller than the lattice constant of the substrate which are alternatingly laminated on the substrate, wherein the average strain of the stress compensation strained quantum well layer is a positive quantity. Therefore, the critical thickness of the strained quantum well layer is increased so that the degree of freedom in designing the strained quantum well layer is increased, resulting in a semiconductor device with improved characteristics.

Claims

1. A semiconductor device comprising:

a substrate having a lattice constant a_s ; and

a stress compensation strained quantum well layer having an average strain ε

_average and comprising a plurality of compressively strained layers, each compressively strained layer having a lattice constant a₁ larger than a_s and a thickness t₁, to which a strain ε

₁ (|ε

₁ |>

0.001) that is equal to (a₁ -a_s)/a_s is applied, and a plurality of tensively strained layers, each tensively strained layer having a lattice constant a₂ smaller than a_s and a thickness t₂, to which a strain ε

₂ (|ε

₂ |>

0.001) that is equal to (a₂ -a_s)/a_s is applied, said compressively strained layers and said tensively strained layers being alternatingly laminated on the substrate, wherein the average strain ε

_average of the stress compensation strained quantum well layer that is equal to (ε

₁ ·

t₁ +ε

₂ ·

t₂)/(t₁ +t₂) is in a range from +0.2% to +0.6%.

2. The semiconductor device of claim 1 wherein said semiconductor device is a semiconductor laser including the stress compensation strained quantum well layer as an active layer.

3. The semiconductor device of claim 1 wherein said semiconductor device is a semiconductor optical modulator including the stress compensation strained quantum well layer as an optical waveguide layer.