TLM fit

This example shows how to perform the curve-fitting via Quokka3 simulations required for the biTLM method. It thereby shows how to use the optimizer functionality of Quokka3, and how to simulate a resistance test structure.

It is well.known that for the case of full-area passivating contacts which are metallized only locally (e.g. industrial n-TOPCon cells or HJT cells), several contact resistances rather than only a single metal-semiconductor resistance matter.

several contact resistivities matter for the case of a rear side passivating contact

Characterizing all those relevant contact resistivities is not trivial, as the standard TLM method is not applicable. For this the biTLM method was proposed, extending the standard TLM method by the same measurement including a full-area metallization to change the current path. The measurement results can be fitted to numerical simulations to discriminate the individual contact resistivities.

biTLM concept: TLM measurement with and without full rear metallization

From: Fell et. al, Why and How to Measure the Non Metallized Contact Resistivity of a Passivating Contact, IEEE PVSC 2020