Electrode Interdependence and Hole Capacitance in the Capacitance -Voltage Characteristics of Hydrogenated Amorphous Silicon Thin-Film Transistors

ABSTRACTThe inter-electrode capacitance - voltage (C-V) characteristics of back-channel etched inverted-staggered hydrogenated amorphous silicon (a-Si:H) thin-film transistors (TFTs) were investigated. It is demonstrated that this simple measurement can be used to diagnose TFT parameters such as the fabricated channel length, the channel resistance, and the error in the mask alignment of the source and drain overlap lengths. The C-V characteristics associated with the hole accumulation in a-Si:H TFTs with n+-type source/drain contacts were also examined. We observed that the a.c. capacitance increases for low frequencies and/or moderately high measurement temperatures provided the gate voltage is sufficiently negative.