Ronald Nelson

US Patent:

42760984, Jun 30, 1981

Filed:

Mar 31, 1980

Appl. No.:

6/135643

Inventors:

Ronald J. Nelson - Berkeley Heights NJ
Phillip D. Wright - New Providence NJ

Assignee:

Bell Telephone Laboratories, Incorporated - Murray Hill NJ

International Classification:

H01L 21208

US Classification:

148171

Abstract:

Discrete InP-InGaAsP mesa double heterostructure lasers have been fabricated by a batch process in which the laser mirrors are formed by chemically etching the wafer from the top surface down into the substrate. A feature of the process is that the metal contact on the top surface is recessed within the periphery of an overlying mask, and the etching time is controlled so that the contact is not undercut by the sidewalls of the mesa. Another feature is the use of a self-limiting etchant which etches the mirrors smoothly and at a faster rate than the sidewalls. Preferably, the mirrors etch isotropically and the sidewalls etch preferentially along crystallographic planes. Also described is subsequent batch processing (e. g. , forming mirror coatings) and on-wafer testing of the etched-mirror lasers.

US Patent:

45661715, Jan 28, 1986

Filed:

Jun 20, 1983

Appl. No.:

6/505993

Inventors:

Ronald J. Nelson - Berkeley Heights NJ
Randall B. Wilson - Maplewood NJ

Assignee:

AT&T Bell Laboratories - Murray Hill NJ

International Classification:

H01L 2120
H01L 21302

US Classification:

29569L

Abstract:

In the fabrication of buried heterostructure InP/InGaAsP lasers, mask undercutting during the mesa etching step is alleviated by a combination of steps which includes the epitaxial growth of a large bandgap InGaAsP cap layer (1. 05 eV. ltorsim. E. sub. g. ltorsim. 1. 24 eV) and the plasma deposition of a SiO. sub. 2 etch masking layer. Alternatively, the cap layer may be a bilayer: an InGaAs layer or narrow bandgap InGaAsP (E. sub. g. ltorsim. 1. 05 eV), which has low contact resistance, and a thin InP protective layer which reduces undercutting and which is removed after LPE regrowth is complete. In both cases, etching at a low temperature with agitation has been found advantageous.

US Patent:

46619615, Apr 28, 1987

Filed:

Oct 22, 1985

Appl. No.:

6/790072

Inventors:

Ronald J. Nelson - Berkeley Heights NJ
Randall B. Wilson - Maplewood NJ

Assignee:

American Telephone and Telegraph Company, AT&T Bell Laboratories - Murray Hill NJ

International Classification:

H01L 2348
H01S 319

US Classification:

372 46

Abstract:

In the fabrication of buried heterostructure InP/InGaAsP lasers, mask undercutting during the mesa etching step is alleviated by a combination of steps which includes the epitaxial growth of a large bandgap InGaAsP cap layer (1. 05 eV. ltorsim. E. sub. g. ltorsim. 1. 24 eV) and the plasma deposition of a SiO. sub. 2 etch masking layer. Alternatively, the cap layer may be a bilayer: an InGaAs layer or narrow bandgap InGaAsP (E. sub. g. ltorsim. 1. 05 eV), which has low contact resistance, and a thin InP protective layer which reduces undercutting and which is removed after LPE regrowth is complete. In both cases, etching at a low temperature with agitation has been found advantageous.