Fabrication of precision high quality facets on molecular beam epitaxy material
AssigneeThe Regents of the University of California
InventorsHolly E. Petersen, William D. Goward, Sol P. Dijaili
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Abstract
Fabricating mirrored vertical surfaces on semiconductor layered material grown by molecular beam epitaxy (MBE). Low energy chemically assisted ion beam etching (CAIBE) is employed to prepare mirrored vertical surfaces on MBE-grown III-V materials under unusually low concentrations of oxygen in evacuated etching atmospheres of chlorine and xenon ion beams. UV-stabilized smooth-surfaced photoresist materials contribute to highly vertical, high quality mirrored surfaces during the etching.
Claims29
A method for etching a substrate comprising:
- defining a mask comprising a photoresist stabilized with ultraviolet light at relative humidities greater than 50% on a surface of a substrate containing at least a first layer of a first material and a second layer of a second material;
- anisotropically etching said substrate through said mask in an oxygen atmosphere of less than 10−9 Torr to produce a structure in said substrate having a (1) bottom surface comprising said first material and (2) a mirrored sidewall surface comprising said first material and said second material.
A method for etching a semiconductor comprising:
- defining a mask comprising a photoresist stabilized with ultraviolet light at relative humidities greater than 50% on a surface of a body comprising a first compound semiconductor;
- and
- anisotropically etching said semiconductor through said mask under conditions including and energy of less than about 500 eV. in an atmosphere containing oxygen in less than 10−10 Torr to produce a structure in said body having a bottom surface and a sidewall surface comprising said sidewall surface having a roughness less than 10 nm.
A method for fabricating mirrored vertical facets on semiconductor material comprising molecular beam epitaxial grown multilayers containing III-V materials, said method comprising:
- cleaning said semiconductor material;
- depositing a photoresist on said semiconductor material;
- curing said photoresist on said semiconductor material to a thickness in the range from about 1.0 to about 1.2 micron;
- exposing at least a first portion of said photoresist to ultraviolet light through at least one aperture in a mask covering said semiconductor material at relative humidities greater than 50%;
- removing from said semiconductor material said first portion of said photoresist exposed to said ultraviolet light;
- exposing a second portion of said photoresist to ultraviolet light to produce a stabilized second portion of said photoresist;
- hard baking said second portion of said photoresist;
- etching said second portion of said photoresist and said semiconductor material to produce a structure in said semiconductor material having a bottom surface and a mirrored sidewall surface, said etching comprising impinging said photoresist and said semiconductor with an ion beam having an energy less than about 1000 eV in an atmosphere containing oxygen at less than about 10−10 Torr, said ion beam comprising chlorine flowing at a rate from about 2 to about 20 sccm;
- and
- removing a remaining portion of said photoresist.
Dependencies are inferred from the claim text.