AVS 47th International Symposium
    Manufacturing Science and Technology Monday Sessions
       Session MS-MoM

Paper MS-MoM1
Inline Quality Analysis in MBE Manufacturing of AlGaAs/InGaAs pHEMT Structure Using Photoreflectance and Contactless Electromodulation Spectroscopy

Monday, October 2, 2000, 8:20 am, Room 304

Session: Metrology for IC Manufacturing
Presenter: G. Zhou, Alpha Industries, Inc.
Authors: G. Zhou, Alpha Industries, Inc.
W. Liu, Alpha Industries, Inc.
M. Lin, Alpha Industries, Inc.
Correspondent: Click to Email
Molecular beam epitaxy (MBE) has become a predominate technology in the manufacturing of pseudomorphic high electron mobility transistors (pHEMTs) for microwave power amplifiers and switchers. In order to keep ahead of the performance and cost curves, nondestructive inline metrologies which leverage the yield learning curve of the fabricator are required. We report the study of implementation of photoreflectance (PR) and contactless electromodulation spectroscopy (CER) as inline quality monitoring tools for AlGaAs/InGaAs pHEMTs manufacturing. Using the reduced mass deduced from experiments, the built-in electric field, the band-gap and/or Al composition in the barrier region is obtained from the above band-gap Franz-Keldysh oscillations (FKO). Two dimensional electron gas (2DEG) density can also be determined by the line shape fitting of the transitions from InGaAs region, and the statistical data both from PR/CER and Hall measurements on a number of wafers are compared. The quality of the device structure and 2DEG density confined within the InGaAs quantum well are found to have a direct relationship both to the intensity of PR/CER transitions from AlGaAs/GaAs superlattice and the built-in electric field in the AlGaAs barrier layer. This observation reveals the possibility to use PR/CER as a screening technique.