酸化物半導体TFTのシミュレーションモデルの開発

摘要

酸化物半導体a-InGaZnOを用いた薄膜トランジスタ（a-IGZO TFT)に関して,電流電圧特性のシミュレーションモデルを新たに開発した.一次元のポアソン方程式を用いてモデルを開発することで,従来の二次元的な手法に比べて大幅に計算時間を短縮し,さらに,バンドギャップ中の欠陥準位,及びドレイン電流の拡散,ドリフト両成分を考慮することで，高精度なシミュレーションを実現した，開発モデルは,a-IGZO TFTのドレイン電流特性を広範囲なバイアス条件で再現でき,TFTの特性解析や構造設計をより速く正確に行うことが可能となる.%A new simulation model for current-voltage characteristics of oxide semiconductor thin-film transistors (a-IGZO TFTs) is presented. This model is developed on the basis of the one-dimensional Poisson equation to significantly reduce the calculation time as compared to a widely-used two-dimensional approach. Furthermore, the model takes into account trap states in the band gap, and also includes both drift and diffusion components of the drain current for precise simulation. The developed model can accurately reproduce the drain current characteristics of a-IGZO TFTs over a wide range of gate and drain voltages, which enables faster and accurate TFT structure design, as well as characteristic analyses.