The Influence of Fluorinated Silicon Nitride Gate Insulator on Positive Bias Stability toward Highly Reliable Amorphous InGaZnO Thin-Film Transistors
The Influence of Fluorinated Silicon Nitride Gate Insulator on Positive Bias Stability toward Highly Reliable Amorphous InGaZnO Thin-Film Transistors
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DOI：
10.1149/2.014402jss
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发表时间：
2014
影响因子：
2.2
通讯作者：
H. Yamazaki;Y. Ishikawa;M. Fujii;Y. Ueoka;M. Fujiwara;E. Takahashi;Y. Andoh;N. Maejima;H. Matsui;F. Matsui;H. Daimon;Y. Uraoka
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文献类型：
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作者：
H. Yamazaki;Y. Ishikawa;M. Fujii;Y. Ueoka;M. Fujiwara;E. Takahashi;Y. Andoh;N. Maejima;H. Matsui;F. Matsui;H. Daimon;Y. Uraoka
非晶In-Ga-Zn-O薄膜晶体管（a-IGZO）作为传统非晶硅薄膜晶体管（a-Si）的替代器件而备受关注。该材料的特点是制造温度低于200℃，与a- si tft相比，具有更高的场效应迁移率和更低的阈值电压（Vth）等优越的电子性能。这种理想的性能也使我们能够为显示器设计外围电路。此外，a- igzo tft被认为是“透明电子”的一种有前景的材料，因为它们的宽带隙为3.2 eV。1‐4另一方面，一些论文报道了aIGZO tft对电应力的稳定性较差。5‐7由于可靠性是利用透明电子器件中的氧化物半导体实现下一代显示器的一个问题，因此有必要对a- igzo及其问题进行更深入的了解。研究了氮化硅栅极绝缘子（gi）中氢浓度对a-IGZO TFTs电稳定性的影响。8‐10 Lee等人报道了SiNx薄膜中的氢由于电子的浅层电荷捕获位点的产生而强烈地诱导了阈值电压偏移（- V th）。他们的结果使我们期望栅极绝缘体中较低的氢含量将提供相当稳定的tft。在这项研究中，我们提出了一种氟化SiNx薄膜，利用SiH4和N2作为源气体，不同于用SiH4/NH3制备的传统薄膜，并通过施加正偏应力（PBS）研究了a- igzo TFT的电学性质。为了探讨氢氟对红外光谱可靠性的影响，我们在控制氢氟浓度的条件下制备了几种sinx薄膜。热氧化SiO2栅极绝缘子也进行了评价比较。
Amorphous In-Ga-Zn-O thin-film transistors (a-IGZO TFTs) have attracted considerable attention as an alternative device for conventional amorphous silicon (a-Si) TFTs. The features of this material are a low fabrication temperature less than 200 ◦ C, and preferable electronic properties such as higher field-effect mobility and lower threshold voltage (Vth) compared with those of a-Si TFTs. Such desirable performances also enable us to design peripheral circuits for displays. Furthermore, a-IGZO TFTs are regarded as a prospective material for “transparent electronics”, because of their wide bandgap of ∼3.2 eV. 1‐4 On the other hand, several papers have reported that aIGZO TFTs showed poor stability against electrical stresses. 5‐7 Since reliability is an issue for the realization of next-generation displays utilizing oxide semiconductors in transparent electronics, a deeper understanding of a-IGZO and its problems are necessary. The influence of hydrogen concentration in silicon nitride (SiNx) gate insulators (GIs) on the electrical stability of a-IGZO TFTs has been actively discussed. 8‐10 Lee et al. reported that the hydrogen in SiNx film strongly induced threshold voltage shift (�V th) due to the generation of shallow charge-trapping sites for electrons. 11 Their results lead us to expect that lower hydrogen content in the gate insulator will provide quite stable TFTs. In this study, we propose a fluorinated SiNx film utilizing SiF4 and N2 as source gasses unlike conventional film fabricated with SiH4/NH3 and investigated the electrical properties of a-IGZO TFT by applying positive biased stress (PBS). In order to discuss effect on reliability of hydrogen and fluorine in the GIs, we prepared several kindsofSiNx filmswithcontrollingtheconcentrationofhydrogenand fluorine. Thermally-oxidized SiO2 gate insulator was also evaluated for comparison.