Spice model for detection of dynamic threshold voltage shift during failure analysis of oxide TFT‐based AMD gate drivers

We present an accelerated SmartSpice model that can detect dynamic threshold voltage shift (ΔVth)‐related failure of an oxide thin‐film transistor (TFT)‐based gate driver. During gate driver operation, the alternating HIGH and LOW input signals repeatedly stress and relax the TFT components of the gate driver. Because oxide TFTs do not recover completely during the LOW input level, ΔVth cumulated during the HIGH input levels may result in failure of gate drivers. For correct failure analysis, a TFT model that can detect dynamic ΔVth is, therefore, needed to replace current TFT models, as they cannot account for dynamic ΔVth. The model presented herein works correctly with varying temperature and input signals of any shape. A SmartSpice thin‐film transistor (TFT) model that can detect dynamic threshold voltage shift (ΔVth)‐related failure of gate drivers is presented. Alternating HIGH and LOW input signals repeatedly stress and relax gate driver TFTs. Because recovery is incomplete during the LOW input level, the model detects ΔVth that cumulates during the HIGH input level using stress and recovery functions.