In-Situ Sensors for Process Control of CuIn(Ga)Se2 Module Deposition: Final Report, August 15, 2001

This report describes several aspects of in-situ sensors for CIGs module deposition that were explored. First, a composition sensor based on X-ray fluorescence (XRF) was developed that serves as a useful indicator of composition and thickness of CIGS; contains only low-cost, commercially available components; has been verified for accuracy of both in-situ and ex-situ results; has been exposed toover 600 hours of heated Se ambient without detriment; was improved for a 20% increase in signal-to-noise on the second design iteration; and has been used in closed-loop control of CIGS deposition. The XRF sensor is clearly applicable to in-situ CIGS deposition, but is less appropriate for other layers in the module. Second, non-contract infrared thermometry was designed for substratetemperature and emissivity measurement during CIGS deposition. Preliminary measurements have confirmed the validity of the design. However, a number of items remain for future work, including full in-situ testing. Finally, optical emission spectroscopy was considered for control of Se, Cu, In, and Ga rates, but was not pursued due to limited applicability.