Estimation of threshold voltage shift in a-IGZO TFTs under different bias temperature stress by improved stretched-exponential equation

In this work, we study threshold voltage (V
_th
) shift degradation in amorphous IGZO (a-IGZO) TFTs. The TFTs employ the bottom-gate staggered structure with an etch stopped layer. An improvement is presented to well known stretched-exponential equation for the V
_th
shift, and a systematic extraction method is provided. The V
_th
shift in a-IGZO TFTs is estimated quantitatively under different gate bias stress and temperature. Good agreements are obtained between calculated results and measured data.