基于表面势的双栅非晶InGaZnO薄膜晶体管电路仿真模型研究

The double-gate amorphous InGaZnO thin-film transistors (TFTs) have higher electric performance, higher stability, and can simplify the circuit structure, comparing with the single-gate TFTs. The DG TFTs have gained more and more attentions in recent years. In the DG TFTs, the trap states in the channel can affect both the mobility and the charge distribution, and the charge couple between the two gates. The surface potential calculation and charge analysis are the key problems in the modeling of the DG TFTs. This proposal is the continuous work on the proposer’s available research foundation, and develop the surface-potential-based model for the circuit simulation. The main contents are listed as: First, considering the exponential distribution trap states density within the energy gap in the channel material, solving the surface potential equations effectively, analyzing the charge couple, the drain current model and the capacitances model are developed for the DG TFTs with long channel length. Second, analyzing the temperature, electric field enhanced carrier emission mechanism, the leakage current model is developed. Considering the channel length modulation effect, kink effect, and series resistance effect, the compact model is developed for the short channel devices. Third, optimizing the modeling parameters extraction, and realizing the model with the Verilog-A language, the model is verified by the circuit simulation. The proposal develop the compact model for the DG amorphous InGaZnO TFTs, is useful and important for the integrated circuit design.

与单栅结构相比，双栅结构的非晶InGaZnO薄膜晶体管能增强电学性能、提高稳定性、简化电路结构，已成为近年来的研究热点。该器件沟道区存在陷阱态，会同时影响迁移率和电荷分布，且双栅之间存在电荷耦合，其建模存在表面势计算和电荷分析的技术难点。本项目拟在已有研究基础上，开发基于表面势的电路仿真模型，主要内容包括：第一，基于沟道材料带隙中指数分布的陷阱态密度，高效求解表面势，分析电荷耦合关系，建立长沟道器件的电流和电容模型；第二，分析温度、电场增强的载流子发射机理，建立泄漏电流模型，并考虑沟道长度调制、kink效应和串联电阻效应，建立适用于短沟道器件的集约模型；第三，优化模型参数的提取流程，用Verilog-A语言实现模型，并进行电路仿真验证。项目开发双栅非晶InGaZnO薄膜晶体管的集约模型，对相关集成电路设计产业，具有深远的意义。

非晶InGaZnO薄膜晶体管（TFT）的载流子迁移率比非晶硅TFT高，大面积均匀性比多晶硅TFT好，已经成为新一代平板显示技术中的关键器件。建立基于器件物理解析的电流模型，一方面有利于深入理解TFT中的载流子输运机制，另一方面有利于开发高效的电路仿真工具。本项目主要研究了非晶InGaZnO-TFT的低频噪声模型和电流模型，并延伸到有机TFT、ZnO-TFT，多晶硅TFT和非晶硅TFT。项目执行期间共发表SCI收录论文3篇，EI、CPCI收录论文5篇，申请专利1项，培养研究生3人、博士后1人。