Semiconductor light emitting element with II-VI and III-V compounds

• US 5,539,239 A
• Filed: 02/17/1995
• Issued: 07/23/1996
• Est. Priority Date: 02/18/1994
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Kawazu, Zempei, Kimura, Tatsuya
• Primary Examiner(s): MINTEL, WILLIAM A
• Application Number:
  US08/390,586
• Time in Patent Office: 522 Days
• Field of Search: 257/94, 257/95, 257/96, 257/97, 257/103, 257/13, 372/44, 372/45, 372/46
• US Class Current: 257/94
• CPC Class Codes: H01L 33/0087 with a substrate not being a II-VI compound
• CPC Class Codes: H01L 33/26 Materials of the light emitting region
• CPC Class Codes: H01S 5/327 in AIIBVI compounds, e.g. ZnCdSe-laser

Abstract

A semiconductor light emitting element includes a wide band gap energy II-VI semiconductor layer on a p type III-V semiconductor substrate and a III-V semiconductor buffer layer between the semiconductor substrate and the wide band gap energy II-VI semiconductor layer having a band gap energy intermediate those of the semiconductor substrate and the wide band gap energy II-VI semiconductor layer. Energy spikes in the valence band of the element are reduced and the injection efficiency of holes is increased so that a semiconductor light emitting element having a low operation voltage is produced.

Claims

1. A semiconductor light emitting element comprising:

a p type GaAs substrate having a band gap energy;

a p type ZnSe layer disposed on said GaAs substrate and having a band gap energy; and

a p type (Al_x Ga_1-x)_y In_1-y P buffer layer disposed between said p type GaAs substrate and said p type ZnSe layer and having a band gap energy larger than the band gap energy of said p type GaAs substrate and smaller than the band gap energy of said ZnSe layer wherein 0<

x<

1, 0.16<

y<

1 and the band gap energy of said buffer layer monotonically increases from 1.42 eV to 2.45 eV from said p type GaAS substrate to said p type ZnSe layer.

5. The semiconductor light emitting element of claim 1 wherein said p type (Al_x Ga_1-x)_y In_1-y P buffer layer has a lattice constant that varies with position between said substrate and said ZnSe layer and matches the lattice constant of said ZnSe layer at said ZnSe layer.

2. A semiconductor light emitting element comprising:

a p type GaAs substrate having a band gap energy;

a p type ZnSe layer disposed on said p type GaAs substrate and having a band gap energy; and

a buffer layer of (Al_z Ga_1-z)As, wherein 0<

z<

1, disposed between said p type GaAs substrate and said ZnSe layer and having a band gap energy larger than the band gap energy of said p type GaAs substrate and smaller than the band gap energy of said ZnSe layer.

3. A semiconductor light emitting element comprising:

a p type III-V semiconductor substrate having a band gap energy;

a wide band gap energy II-VI semiconductor layer disposed on said p type III-V semiconductor substrate and having a band gap energy;

a III-V semiconductor buffer layer disposed between said III-V semiconductor substrate and said wide band gap energy II-VI semiconductor layer and having a band gap energy larger than said III-V semiconductor substrate;

a III-V semiconductor layer having a band gap energy larger than said III-V semiconductor substrate disposed on only part of said III-V semiconductor substrate as a current injecting region.

4. The semiconductor light emitting element of claim 3 wherein:

said III-V semiconductor substrate is GaAs;

said wide band gap energy II-VI semiconductor layer is p type ZnSe; and

said III-V semiconductor layer having a larger band gap energy than said III-V semiconductor substrate is (Al_x Ga_1-x)_y In_1-y P.