Capacitance–Voltage Measurement With Photon Probe to Quantify the Trap Density of States in Amorphous Thin-Film Transistors

Abstract

We report on a characterization method to quantitatively estimate the interfacial trap density of states (DOS) in thin-film transistors (TFTs): photon-probe capacitance-voltage ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CV</i> ) measurement. The photo- <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CV</i> method was compared to photoexcited charge-collection spectroscopy, which is another photon-probe method using current-voltage ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</i> - <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> ) measurement to meet the same purpose. Here, we directly characterized the DOS of amorphous-Si- and amorphous-InGaZnO-based TFTs using the photon-probe <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CV</i> measurement, and the results turned out to mainly focus the trap DOS at channel/dielectric interface. On the one hand, the DOS profile by photon-probe <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</i> - <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> method appeared to give additional trap information from the transistor back channel.