Samsung Advanced Institute of Technology

This study investigates the hole and electron conduction properties of thin-film transistors

(TFTs) with tin monoxide (SnO) channel and indium tin oxide (ITO) source/drain (S/D)

electrodes, considering the adoption to three-dimensional (3D) NAND Flash. Compared to

SnO TFTs with gold (Au) S/D electrodes, significant enhancement of electron conduction was

observed when adopting ITO S/D electrodes. The ITO electrodes decreased the Schottky

barrier height for electron injection, enhancing electron conduction and consequently inducing

ambipolar conduction behavior. The ambipolar SnO TFT exhibited coexisting electron and

hole channels, which induced a transition from normal to abnormal conduction properties.

These transitioning conduction characteristics were analyzed, and a method to extract

saturation mobility in ambipolar TFTs considering the electron-hole (e-h) recombination effect

was proposed. Furthermore, bias-stress stability tests were conducted to examine the effect of

the coexisting electron and hole channels on the carrier-trapping properties. This analysis

provides valuable insights into the electrical characteristics of ambipolar TFTs, considering the

coexisting electron and hole channels.