Dealing with Leakage Current in TLM and CTLM Structures with Vertical Junction Isolation

Transmission line method (TLM) structures are often employed to extract contact resistivity between a metal and a doped semiconductor region. In this article we treat the situation where the doped region is junction-isolated from the substrate. The junction isolation may be leaky resulting in erroneous parameter extraction. The effect of junction leakage is treated both theoretically and through exemplary wafer-level CTLM measurement results on photovoltaic cells (solar cells) and epi-wafer samples. This paper describes how reliable contact resistivity values can be obtained using the transmission line method on junction isolated structures