Extraction of Contact Resistance and DC Modeling in Metal Oxide TFTs

Based on the device physics, a simple and fast method of extracting contact resistance in metal oxide thin-film transistors (MOTFTs) is proposed through the I-V characteristics. This method divides the channel into two parts: the contact channel and the intrinsic channel, and assumes the electrons injected into the active layer at the source side are completed in the line injection. Using the I-V characteristics, the contact voltage can be obtained, and then the contact resistance can be extracted. The results indicate that contact resistance in MOTFTs depends on V
_g
, V
_d
, and L. Applying the extraction results, a dc drain current model considering contact resistance is proposed. Using this model, we can accurately describe the measurements of MOTFTs with channel lengths scaling from 50 μm to 10 μm. Through the extensive comparisons between the model results and the numerical iteration or experimental data, the validity of the method is strongly supported. This extraction method uses non-numerical iteration, which is simple, fast, and accurate.