Monitoring and Control of Chemical Composition of InGaN Layers During MOCVD
Award last edited on: 5/22/2015

Sponsored Program
Awarding Agency
Total Award Amount
Award Phase
Solicitation Topic Code
Principal Investigator
George Atanasoff

Company Information

AccuStrata Inc

5000 College Avenue Suite 3102
College Park, MD 20740
   (301) 314-2116
Location: Single
Congr. District: 05
County: Prince Georges

Phase I

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Start Date: ----    Completed: ----
Phase I year
Phase I Amount
Metal-Organic Chemical Vapor Deposition (MOCVD) epitaxial processes are used to deposit the GaN, InGaN, AlGaN and other wide band-gap semiconductor thin films making up the buffer, quantum well, and cap layers of the next generation high- brightness LEDs (HB-LEDs) for Solid State Lighting (SSL). Non-uniformity of the central wavelength over the wafers, batch-to-batch and reactor-to-reactor non-repeatability are primary contributors to reduced manufacturing yield. On the epitaxial level, non-uniform device performance results from the variations of chemical composition and thickness of the individual InGaN quantum well layers. Being extremely thin, the individual quantum well layers remain beyond the resolution of the standard optical monitoring techniques. This SBIR Phase I projects objective is to research and develop a prototype of optical monitoring and control system utilizing AccuStratas know-how in real-time optical monitoring, intelligent data-mining and process modeling, which has already been commercially demonstrated in the PV industry. AccuStrata will develop, install and validate on a commercial MOCVD reactor an alpha-prototype of a spectroscopic optical monitoring and process control system. The system will monitor the LED thin films as they grow in real time on the individual wafers, record the signal in a broad spectral range and process the information to retrieve the most important film parameters and their distribution over a single wafer, all the wafers in a batch and multiple batches. During the epitaxial growth of the thin quantum well films, the recorded spectral signal will be correlated to the process parameters such as substrate temperature and precursor gas composition. AccuStrata will deploy a novel algorithm for a real-time pattern search in the acquired broadband spectral data and display any abnormalities and differences in the deposition of the individual quantum well layers. This information can be used by the MOCVD engineer to better tune the epitaxial process, and later can be integrated into the MOCVD reactor to ensure better repeatability of the individual quantum well layers in the LED structure and allow tightening of the distribution of the LED central wavelength. The monitoring and control system will shorten the time for manufacturing high quality LEDs, reduce non-uniformity on a single wafer and batch-to-batch and reactor-to-reactor variations. It will enable manufacturing of new generation HB-LED with improved efficacy and lower cost, needed for faster adoption of SSL.

Phase II

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Phase II year
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This project addresses the problems of reduced manufacturing yield and high manufacturing cost, which are major causes for slower adoption of Solid State Lighting (SSL) in daily life. The proposed work will result in improved quality of the semiconductor epitaxial process the basic process in manufacturing of LED devices