NOVELTY - A method (M1) for etching the surface of a cadmium-tellurium (CdTe)-containing layer involves providing a CdTe-containing layer; and providing an etching composition to etch at least part of the layer, where the etching composition comprises an acid, an oxidizer, and a complexing agent.    USE - For etching the surface of a cadmium-tellurium (CdTe)-containing layer (claimed) used in the manufacturing process for thin film solar cells and in the manufacture of semiconductor, photovoltaic, LCD-TFT, and flat panel type devices.    ADVANTAGE - The etching process provides improved stability of the solar cells and increased solar efficiency. The presence of the oxide-free Te-rich layer, combined with the copper complexing agent, keeps the copper at the back contact rather than allowing it to diffuse through the CdTe-containing layer to the CdS junction. The etching compositions are less aggressive than prior art etching compositions and therefore may be applied to thinner CdTe-containing layers for longer periods of time. By being less aggressive, the etching compositions allow for wider manufacturing process windows than the prior art etching compositions, which provides more flexibility in the manufacturing process and the potential ability to recover from human and/or mechanical error. The etching compositions need not be rinsed from the CdTe-containing layer by deionized water after the etching step. The etching compositions are less aggressive than the prior art etching compositions, resulting in a much slower etch rate. Removing the rinsing step from the prior art etching process also provides for improved manufacturing efficiencies by reducing the total number of steps in the manufacturing process. The etching composition prevents copper-containing dopant from migrating into the CdTe-containing layer and rendering the resulting solar cell less effective. The composition maintains the power output of the solar cell over longer period of time.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) a method (M2) for etching the surface of a CdTe-containing layer involving: providing a CdTe-containing layer; and providing an etching composition to etch at least part of the layer, where the etching composition comprises a first mixture containing an acid and an oxidizer and a second mixture containing a complexing agent; and    (2) a composition for etching a CdTe-containing layer, comprising: approximately 5 to approximately 50 wt./wt.% of an acid; approximately 0.5 to approximately 5 wt./wt.% of an oxidizer; and approximately 0.01 to approximately 3 wt./wt.% of a complexing agent.