Negative bias temperature instability of Rf-sputtered Mg 0.05Zn0.95O thin film transistors with MgO gate dielectrics
Journal
Semiconductor Science and Technology
Journal Volume
26
Journal Issue
10
Date Issued
2011
Author(s)
Abstract
This study investigated the negative bias temperature instability of rf-sputtered bottom-gate Mg0.05Zn0.95O active layer thin-film transistors (TFTs) annealed at 200 ¢XC for 5 h and 350 ¢XC for 30 min. The TFT devices initially exhibited similar electrical characteristics. When TFTs were stressed at room temperature, the TFTs (in both annealing conditions) showed typical negative shift of threshold voltage (£GV th). When TFTs were stressed at 80 ¢XC, a turnaround of £GVth appeared for the 200 ¢XC-annealed TFTs; the V th shifted toward a negative direction initially and consequently turned positive. The turnaround phenomenon should result from the competing charge trapping and defect creation. On the other hand, the 350 ¢XC-annealed TFTs still showed typical negative shift of threshold voltage when stressed at 80 ¢XC. ? 2011 IOP Publishing Ltd.
Type
journal article