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氧气流量对InGaSnO薄膜晶体管性能的影响研究

Investigation on the Effects of Oxygen Flow Rate for the Performance of InGaSnO Thin Film Transistors

  • 摘要: 采用射频磁控溅射方法,利用P+Si/SiO2衬底在室温下制备新型 InGaSnO (IGTO)氧化物薄膜晶体管。通过控制氧气流量(0,1,3,5 sccm)来探究不同氧气流量对IGTO薄膜晶体管的电学特性以及稳定性的影响。XRD表征结果证实,在不同氧气流量下所制备的 IGTO 薄膜均为非晶结构。XPS分析表明,随着氧气流量的增加,IGTO薄膜中氧空位占比呈下降趋势,其从35.2%降至27.6%。氧气浓度过大会造成吸附氧等受主缺陷增多,更易发生载流子的散射。实验结果表明,当采用氩氧比为 Ar: \textO_\text2 =27:3 时,器件展现出优异的电学特性和稳定性,其场效应迁移率为 19.2 cm2/Vs,亚阈值摆幅为 0.5 V·dec−1。这是因为氧气流量为 3 sccm 时薄膜生长过程中氧原子供应充足,氧空位被有效填充使得缺陷态密度降低而致使陷阱效应减弱,栅极电压的微小变化就有利于调控沟道载流子浓度,最终有效改善和提高 IGTO 薄膜晶体管的性能。

     

    Abstract: New oxide InGaSnO (IGTO) thin-film transistors (TFTs) were fabricated at room temperature using a P+Si/SiO2 substrate via radio-frequency magnetron sputtering. The effects of varying oxygen flow rates (0, 1, 3, 5 sccm) on the electrical properties and stability of the IGTO thin-film transistors were investigated. XRD characterization results confirm that IGTO films prepared under different oxygen flow rates all exhibit an amorphous structure. XPS analysis indicates that as the oxygen flow rate increases, the proportion of oxygen vacancies within the IGTO film decreased from 35.2% to 27.6%. Excessive oxygen concentration leads to an increase in acceptor defects such as adsorbed oxygen, thereby enhancing carrier scattering. Experimental results indicate that when employing an argon-oxygen ratio of Ar:O = 27:3, the device exhibits suitable electrical characteristics and stability, which are including a field-effect mobility of 19.2 cm2/V·s and a subthreshold swing of 0.5 V·dec−1. This is because at an oxygen flow rate of 3 sccm, the oxygen supply during film growth is sufficient, thus effectively reducing the oxygen vacancies and defect density. Consequently, small variations in gate voltage can directly modulate the channel carrier concentration, ultimately improving and enhancing the performance of IGTO TFTs.

     

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