A Surface-Potential-Based Drain Current Compact Model of Dynamic-Depletion Polysilicon Thin-Film Transistors.

An analytical surface-potential-based drain current model of dynamic-depletion (DD) polysilicon (poly-Si) thin-film transistors (TFTs) is proposed in this paper. In the 1-D Poisson equation, total charge density is reformulated by an effective charge density, which allows a closed-form surface potential calculation scheme. Different boundary conditions between partial depletion and full depletion are calculated and unified into one back-gate potential in the DD mode, which allows a unified-form surface potential calculation scheme. Combining with Gauss’s theory, we explicitly solve a closed- and unified-form surface potential of DD poly-Si TFTs. Based on the solution of the surface potential, the drain current is derived analytically from the Pao–Sah integration. Furthermore, our solution is verified by numerical results and experimental data, respectively. As a result, such a model can accurately predict I–V characteristics of DD poly-Si TFTs and provide computational efficiency for TFT process optimization and circuit simulations. [ABSTRACT FROM AUTHOR]