Determination of bulk and interface density of states in metal oxide semiconductor thin-film transistors by using capacitance–voltage characteristics
Department of Electronic Engineering, Jinan University, Guangzhou 510630, PR China
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Received in final form: 16 August 2017
Accepted: 30 August 2017
Published online: 5 October 2017
A physical-based straightforward extraction technique for interface and bulk density of states in metal oxide semiconductor thin film transistors (TFTs) is proposed by using the capacitance–voltage (C–V) characteristics. The interface trap density distribution with energy has been extracted from the analysis of capacitance–voltage characteristics. Using the obtained interface state distribution, the bulk trap density has been determined. With this method, for the interface trap density, it is found that deep state density nearing the mid-gap is approximately constant and tail states density increases exponentially with energy; for the bulk trap density, it is a superposition of exponential deep states and exponential tail states. The validity of the extraction is verified by comparisons with the measured current–voltage (I–V) characteristics and the simulation results by the technology computer-aided design (TCAD) model. This extraction method uses non-numerical iteration which is simple, fast and accurate. Therefore, it is very useful for TFT device characterization.
© EDP Sciences, 2017