Process for the production of an optoelectronic component having a defined axial variation of the coupling coefficient and a defined axial distribution of the phase shift

• US 5,601,731 A
• Filed: 03/09/1995
• Issued: 02/11/1997
• Est. Priority Date: 03/09/1994
• Status: Expired due to Fees

• Current Assignee: Marconi UK Intellectual Property Limited (Marconi Holdings Company Limited)
• Original Assignee: Ant Nachrichtentechnik GmbH
• Inventors: Hillmer, Hartmut
• Primary Examiner(s): POWELL, WILLIAM A
• Application Number:
  US08/401,168
• Time in Patent Office: 705 Days
• Field of Search: 216/2, 216/24, 216/41, 216/11, 156/649.1, 156/654.1, 156/655.1, 156/659.11
• US Class Current: 438/32
• CPC Class Codes: G02B 2006/12176 Etching
• CPC Class Codes: G02B 5/1857 using exposure or etching means, e.g. holography, photolithography, exposure to electron or ion beams
• CPC Class Codes: G02B 6/124 Geodesic lenses or integrated gratings
• CPC Class Codes: G03F 7/001 Phase modulating patterns, e.g. refractive index patterns
• CPC Class Codes: H01S 5/10 Construction or shape of the optical resonator , e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region H01S5/20 takes precedence
• CPC Class Codes: H01S 5/1021 Coupled cavities H01S5/14 takes precedence
• CPC Class Codes: H01S 5/1064 varying width along the optical axis
• CPC Class Codes: H01S 5/12 the resonator having a periodic structure, e.g. in distributed feedback [DFB] lasers comprising a photonic bandgap structure H01S5/11; surface-emitting lasers H01S5/18
• CPC Class Codes: H01S 5/1231 Grating growth or overgrowth details
• CPC Class Codes: H01S 5/1237 Lateral grating, i.e. grating only adjacent ridge or mesa

Abstract

The process for production of an optoelectronic component having a predetermined coupling coefficient distribution and a predetermined phase shift distribution includes providing a photomask defining lateral and axial geometry of the grating fields of the optoelectronic compound, particularly predetermined curved grating boundaries between regions of the optoelectronic component having the grating fields and grating-free regions; performing a spin-on deposition of a photoresist on the semiconductor layers of a semiconductor substrate; structuring the semiconductor layers so that a DFB or DBR grating structure is located between the spin-on photoresist and the semiconductor substrate; after performing the spin-on deposition of the photoresist, exposing the photoresist using the provided photomask to form the optoelectronic component in the semiconductor substrate; and after the exposing of the photoresist using the photomask, etching surfaces of the optoelectronic component which are to be free of the grating fields to remove material to a minimum depth reaching a horizontal xz-plane corresponding to deepest points in the grating trenches of the grating fields.

Claims

1. Process for production of an optoelectronic component having a defined coupling coefficient distribution and a defined phase shift distribution, the optoelectronic component comprising a semiconductor substrate provided with a plurality of semiconductor layers arranged in a vertical direction in the semiconductor substrate and with a DFB or DBR grating structure provided with a plurality of grating trenches having a grating trench depth (a), using semiconductor structuring techniques including photoresist techniques and etching techniques, said process comprising the steps of:

a) providing a photomask defining lateral and axial geometry of grating fields of the optoelectronic component, the defining of the lateral and axial geometry of the grating fields including defining grating boundaries between regions of the optoelectronic component having the grating trenches and grating-free regions, said grating boundaries having a mathematical curvature;

b) performing a spin-on deposition of a photoresist on the semiconductor layers of the semiconductor substrate;

c) structuring the semiconductor layers so that the DFB or DBR grating structure is located between the spin-on photoresist and the semiconductor substrate;

d) after performing the spin-on deposition of the photoresist in step b), exposing the photoresist using the photomask provided in step a) to form the optoelectronic component in the semiconductor substrate; and

e) after the exposing of step d), etching surfaces of the optoelectronic component which are to be free of the grating fields to remove material to a minimum depth reaching a horizontal xz-plane passing through the semiconductor substrate corresponding to deepest positions in the grating trenches of the grating fields.

2. Process as defined in claim 1, wherein the spin-on deposition of the photoresist is performed so that said photoresist is directly spun on the grating structure and wherein said minimum depth of material removal corresponds to the grating trench depth (a).

3. Process as defined in claim 1, further comprising providing additional semiconductor layers on the grating structure, said additional semiconductor layers having a total thickness (b) above the grating structure, and wherein the photoresist is spun-on the additional semiconductor layers and the minimum depth of the material removal corresponds to a sum of the total thickness (b) of the semiconductor layers and the grating trench depth (a).