AVS 50th International Symposium
    Manufacturing Science and Technology Wednesday Sessions
       Session MS-WeM

Paper MS-WeM2
Real-time In-situ Chemical Sensing in GaN MOCVD for Advanced Process Control

Wednesday, November 5, 2003, 8:40 am, Room 326

Session: Sensors, Metrology, and Control
Presenter: S. Cho, University of Maryland
Authors: S. Cho, University of Maryland
G.W. Rubloff, University of Maryland
M.E. Aumer, Northrop Grumman Corporation
D.B. Thomson, Northrop Grumman Corporation
D.P. Partlow, Northrop Grumman Corporation
Correspondent: Click to Email
Gallium nitride is a strong candidate material for next generation semiconductor devices for high frequency, high power electronic applications. Despite the potential of this material, the industry has yet to realize a systematic methodology for reproducible manufacturing at the high performance levels envisioned. As a joint project between the University of Maryland and Northrop Grumman, we have addressed this challenge with the use of a real-time in-situ chemical sensing technique. Residual gas analysis downstream to the MOCVD process has enabled us to monitor in real-time the by-product species due to the deposition reaction as well as other background impurity species inherent to the process. A metric derived from the by-product signals provided us with a real-time means for accurately predicting the crystal quality of the material as determined by the post-process ex-situ XRD (X-ray Diffraction) with an average uncertainty of 5% or less. Background impurity levels in the gas-phase were also closely correlated to the post-process ex-situ PL (Photoluminesence) measurements for material quality. In addition, time-integration of the by-product signals during the deposition process generated metrology for predicting and controlling the thickness of the individual layers in the GaN-based HFET structure. This creates opportunities for advanced process control based on real-time in-situ sensing, with the promise of major benefit in reproducibility and cost reduction in GaN-based semiconductor manufacturing.