Analytical equations are developed for electrostatic assessment of accumulation-mode thin-film transistors (TFTs) so that potential, electric field, and accumulation layer free electron concentration profiles may be generated. Additionally, equations are derived for plotting TFT trap density versus surface potential, based on accurate extraction of the channel mobility as a function of gate voltage. A key factor in formulating these device physics equations is distinguishing between a ‘long-base’ or ‘short-base’ channel thickness. A ‘long-base’ (‘short-base’) channel thickness is defined to occur when the accumulation layer thickness (as calculated in the normal manner) is less than (greater than) the physical thickness of the channel layer. The electrostatic equations derived herein are applied to the analysis of two amorphous oxide semiconductor (AOS) TFTs with differing channel layers, i.e., a 40 nm amorphous indium gallium zinc oxide (a-IGZO) or a 7 nm amorphous indium zinc oxide (a-IZO). Application of these equations suggests that optimal TFT performance is obtained when the channel layer thickness is chosen to be similar to its Debye length. Estimated trap densities of these two AOS TFTs are found to be quite similar. Therefore, the superior mobility performance of the a-IZO TFT compared to the a-IGZO TFT is ascribed to the smaller effective mass of a-IZO, assuming that the maximum (no trapping) drift mobility in the channel is established by the thermally-limited diffusive mobility.

分析方程被开发用于累积模式薄膜晶体管 (TFT) 的静电评估，以便可以生成电势、电场和累积层自由电子浓度分布。此外，基于准确提取作为栅极电压函数的沟道迁移率，导出了用于绘制 TFT 陷阱密度与表面电位的方程。制定这些器件物理方程的一个关键因素是区分“长基”或“短基”通道厚度。“长基”（“短基”）沟道厚度定义为当累积层厚度（以正常方式计算）小于（大于）沟道层的物理厚度时出现。本文导出的静电方程应用于分析具有不同沟道层的两个非晶氧化物半导体 (AOS) TFT，即 40 nm 非晶氧化铟镓锌 (a-IGZO) 或 7 nm 非晶氧化铟锌 (a-伊佐）。这些方程的应用表明，当沟道层厚度选择为与其德拜长度相似时，可以获得最佳的 TFT 性能。发现这两个 AOS TFT 的估计陷阱密度非常相似。因此，与 a-IGZO TFT 相比，a-IZO TFT 的优异迁移率性能归因于 a-IZO 的较小有效质量，假设沟道中的最大（无俘获）漂移迁移率是由热-有限的扩散迁移率。40 nm 非晶氧化铟镓锌 (a-IGZO) 或 7 nm 非晶氧化铟锌 (a-IZO)。这些方程的应用表明，当沟道层厚度选择为与其德拜长度相似时，可以获得最佳的 TFT 性能。发现这两个 AOS TFT 的估计陷阱密度非常相似。因此，与 a-IGZO TFT 相比，a-IZO TFT 的优异迁移率性能归因于 a-IZO 的较小有效质量，假设沟道中的最大（无俘获）漂移迁移率是由热-有限的扩散迁移率。40 nm 非晶氧化铟镓锌 (a-IGZO) 或 7 nm 非晶氧化铟锌 (a-IZO)。这些方程的应用表明，当沟道层厚度选择为与其德拜长度相似时，可以获得最佳的 TFT 性能。发现这两个 AOS TFT 的估计陷阱密度非常相似。因此，与 a-IGZO TFT 相比，a-IZO TFT 的优异迁移率性能归因于 a-IZO 的较小有效质量，假设沟道中的最大（无俘获）漂移迁移率是由热-有限的扩散迁移率。发现这两个 AOS TFT 的估计陷阱密度非常相似。因此，与 a-IGZO TFT 相比，a-IZO TFT 的优异迁移率性能归因于 a-IZO 的较小有效质量，假设沟道中的最大（无俘获）漂移迁移率是由热-有限的扩散迁移率。发现这两个 AOS TFT 的估计陷阱密度非常相似。因此，与 a-IGZO TFT 相比，a-IZO TFT 的优异迁移率性能归因于 a-IZO 的较小有效质量，假设沟道中的最大（无俘获）漂移迁移率是由热-有限的扩散迁移率。