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Photoelectrochemical Etching for Chip Shaping Of LEDs
Technology Benefits
Increased external quantum efficiencyLow cost etchingRapid etchingEliminate the need of mechanical etchingPossible automation of the etching process
Technology Application
SemiconductorsLED shaping
Detailed Technology Description
Researchers at the University of California, Santa Barbara have developed a novel process to chip shape LEDs though photochemical (PEC) etching. This process can directly etch the material in between LEDs that are grown on III-V substrates. By varying the angle of the incident light during PEC etching, the angle of the resulting sidewalls can be controlled to create sloped sidewalls. These walls can then scatter guided modes out of the material rather than reflecting them back, to increase the external quantum efficiency.
Supplementary Information
Patent Number: US8569085B2 Application Number: US2009576946A Inventor: Tamboli, Adele | Hu, Evelyn L. | Speck, James S. Priority Date: 9 Oct 2008 Priority Number: US8569085B2 Application Date: 9 Oct 2009 Publication Date: 29 Oct 2013 IPC Current: H01L002100 | H01L003100 US Class: 438031 | 257079 | 257E21599 | 257E33023 Assignee Applicant: The Regents of the University of California Title: Photoelectrochemical etching for chip shaping of light emitting diodes Usefulness: Photoelectrochemical etching for chip shaping of light emitting diodes Summary: Method of fabricating a semiconductor device. Novelty: Fabrication of semiconductor device by performing photoelectrochemical etch for chip shaping of device comprising Groups III-V semiconductor material in order to extract light emitted into guided modes trapped in semiconductor material
Industry
Electronics
Sub Group
Semiconductor
Application No.
8569085
Others
Background
Light emitting diodes’ (LEDs) external quantum efficiency is limited by light emitted into guided modes being trapped in the material. When wafers are diced, the resulting sidewalls are smooth and vertical resulting in most of the light reflecting back into the material where it is eventually lost. To counteract this phenomenon, shaping is done to modify the geometry to form non rectilinear designs, which decrease the amount of trapped light. This chip shaping involves shaping the material and substrate which may have different compositions. Moreover, the shaping is typically accomplished through crystallographic wet or dry etching or by device sawing using specialty blades.
