Selectively Nitrogen Doped ALD-IGZO TFTs with Extremely High Mobility and Reliability

Abstract

Achieving high mobility and reliability in atomic layerdeposition(ALD)-based IGZO thin-film transistors (TFTs) with an amorphous phaseis vital for practical applications in relevant fields. Here, we suggesta method to effectively increase stability while maintaining highmobility by employing the selective application of nitrous oxide plasmareactant during plasma-enhanced ALD (PEALD) at 200 & DEG;C processtemperature. The nitrogen-doping mechanism is highly dependent onthe intrinsic carbon impurities or nature of each cation, as demonstratedby a combination of theoretical and experimental research. The Ga2O3 subgap states are especially dependent on plasmareactants. Based on these insights, we can obtain high-performanceindium-rich PEALD-IGZO TFTs (threshold voltage: -0.47 V; field-effectmobility: 106.5 cm(2)/(V s); subthreshold swing: 113.5 mV/decade;hysteresis: 0.05 V). In addition, the device shows minimal thresholdvoltage shifts of +0.45 and -0.10 V under harsh positive/negativebias temperature stress environments (field stress: ±2 MV/cm; temperature stress: 95 °C) after 10000 s.