Widely Adjusting the Breakdown Voltages of Kilo-Voltage Thin Film Transistors

High-voltage thin-film transistors (HV-TFTs) with designed field-plates are experimentally demonstrated to work in a wide range of kilo-voltage (kV) and with the tunable breakdown voltages (
${V}_{{\mathrm {BD}}}$
). The field plates have been placed in different positions and biased at different voltages to investigate how to effectively enhance
${V}_{{\mathrm {BD}}}$
. The largest
${V}_{{\mathrm {BD}}}$
is up to 263 % of the case without field plate and reaches 1902.5 V. By monitoring the electric potential at the end of the gated channel (
${V}_{1}$
), it is revealed that the enhanced
${V}_{{\mathrm {BD}}}$
is associated with a reduced
${V}_{1}$
. Therefore, the device breakdown is in fact caused by the breakdown of dielectric near the end of the gated channel in HV-TFTs rather than the destruction of semiconductor near the drain in regular TFTs. This study unveils the breakdown mechanisms of HV-TFTs and provides an effective design route for balancing the breakdown voltages and on-current of the HV-TFTs.