AVS 47th International Symposium
    Material Characterization Tuesday Sessions
       Session MC-TuP

Paper MC-TuP10
Strategies for Reducing the Effects of Topography in Depth Profile Analysis of Polycrystalline Thin Film CdTe/CdS Photovoltaic Materials and Devices

Tuesday, October 3, 2000, 5:30 pm, Room Exhibit Hall C & D

Session: Poster Session
Presenter: S.E. Asher, National Renewable Energy Laboratory
Authors: S.E. Asher, National Renewable Energy Laboratory
M.R. Young, National Renewable Energy Laboratory
H. Moutinho, National Renewable Energy Laboratory
T. Gessert, National Renewable Energy Laboratory
R.G. Dhere, National Renewable Energy Laboratory
P. Sheldon, National Renewable Energy Laboratory
Correspondent: Click to Email
Polycrystalline thin film materials are promising for low-cost, large area manufacturing of photovoltaic modules. Surface analysis methods are critical tools to measure the distribution of contaminants and dopants in these materials. However, the native t opography and heterogeneity can present significant challenges for depth profile analysis, particularly by SIMS. We have developed several methods that have proved useful for SIMS examinations of CdTe/CdS solar cells made by different thin film depositio n methods. Depth profile results obtained after chemical etching, controlled polishing and back-side analysis show strengths and limitations of each method. These methods have allowed us to study diffusion and composition in 100 nm CdS layers buried under up to 10 µm of CdTe. In the films studied, the CdTe may have an initial average surface roughness of @>=@ 200 nm or more. The depth profile results from sample preparation methods listed above will also be compared to depth profiles obtained with sample rotation. We find that sample rotation in these materials is complicated by lateral inhomogeneities, even when the rotation speed is well matched to the cycle time of the analysis.