Temperature of silicon wafers during in-line high-rate evaporation of aluminum

Knowing the substrate temperature during in-line high-rate Al deposition onto silicon solar cells is essential for understanding and improving the deposition process. We deposit 2 and 5 μm-thick aluminum layers at a dynamic deposition rate of 5 μm m/min onto 130 and 180 μm-thick, planar and pyramidally textured, p-type silicon wafers and measure the wafer temperature during the deposition. The temperature depends on the aluminum layer thickness, the wafer thickness, and the wafer emissivity. Two-dimensional finite-element simulations reproduce the measured peak temperatures with an accuracy of 3%.