Avis Christophe, Jang Jin
Advanced Display Research Center, Department of Information Display, Kyung Hee University, Seoul 130-701, Republic of Korea.
Materials (Basel). 2023 Nov 15;16(22):7172. doi: 10.3390/ma16227172.
We studied the impact of NF plasma treatment on the HfO gate insulator of amorphous tin oxide (a-SnO) thin-film transistors (TFTs). The plasma treatment was for 0, 10, or 30 s. The HfO insulator demonstrated a slightly higher breakdown voltage, whereas the capacitance value remained almost constant (~150 nF/cm). The linear mobility slightly increased from ~30 to ~35 cm/Vs when the treatment time increased from 0 to 10 s, whereas a 30 s-treated TFT demonstrated a decreased mobility of ~15 cm/Vs. The subthreshold swing and the threshold voltage remained in the 100-120 mV/dec. range and near 0 V, respectively. The hysteresis dramatically decreased from ~0.5 V to 0 V when a 10 s treatment was applied, and the 10 s-treated TFT demonstrated the best stability under high current stress (HCS) of 100 μA. The analysis of the tin oxide thin film crystallinity and oxygen environment demonstrated that the a-SnO remained amorphous, whereas more metal-oxygen bonds were formed with a 10 s NF plasma treatment. We also demonstrate that the density of states (DOS) significantly decreased in the 10 s-treated TFT compared to the other conditions. The stability under HCS was attributed to the HfO/a-SnO interface quality.
我们研究了氮氟等离子体处理对非晶氧化锡（a-SnO）薄膜晶体管（TFT）的HfO栅极绝缘体的影响。等离子体处理时间分别为0、10或30秒。HfO绝缘体的击穿电压略高，而电容值几乎保持恒定（约150 nF/cm）。当处理时间从0秒增加到10秒时，线性迁移率从约30 cm²/V·s略微增加到约35 cm²/V·s，而经过30秒处理的TFT迁移率降低至约15 cm²/V·s。亚阈值摆幅和阈值电压分别保持在100 - 120 mV/dec.范围内和约0 V附近。当施加10秒处理时，滞后现象从约0.5 V急剧降至0 V，并且经过10秒处理的TFT在100 μA的高电流应力（HCS）下表现出最佳稳定性。对氧化锡薄膜结晶度和氧环境的分析表明，a-SnO保持非晶态，而经过10秒的氮氟等离子体处理会形成更多的金属 - 氧键。我们还证明，与其他条件相比，经过10秒处理的TFT的态密度（DOS）显著降低。高电流应力下的稳定性归因于HfO/a-SnO界面质量。
