TY - JOUR A1 - Slade, Holly C. A1 - Shur, M.S. A1 - Deane, S.C. A1 - Hack, M. T1 - Below threshold conduction in a‐Si:H thin film transistors with and without a silicon nitride passivating layer JF - Applied Physics Letters N2 - We report temperature measurements of inverted staggered amorphous silicon thin film transistor subthreshold conductance for devices with and without a top silicon nitride passivating layer. Subthreshold conductance activation energies clearly show the different conductance paths in the active layer of these devices. Transistors with no top nitride layer conduct in the bulk amorphous silicon, whereas the devices with a top nitride layer conduct at the interface between the amorphous silicon and the top nitride (a ‘‘back’’ channel). Gate bias stressing and light soaking experiments uphold the existence of the back channel. We also present two‐dimensional simulations that support our interpretation of the experimental data. KW - Nitrides KW - Thin film transistors Y1 - 2020 UR - https://doi.org/10.1063/1.117739 VL - 69 IS - 17 SP - 2560 ER - TY - CHAP A1 - Slade, Holly C. A1 - Shur, M.S. A1 - Deane, S.C. A1 - Hack, M. T1 - Physics of Below Threshold Current Distribution in a-Si:H TFTs T2 - Materials Research Society, Proceedings, Amorphous Silicon Technology KW - Thin Film Transistors Y1 - 2020 N1 - Paper recieved a Graduate Research Student Award ER - TY - CHAP A1 - Slade, Holly C. A1 - Shur, M.S. A1 - Deane, S.C. A1 - Hack, M. T1 - Amorphous Silicon TFTs: Material Characterization, Device Operation, and Bias Stress Modeling T2 - The Electrochemical Society Extended Abstracts KW - Thin Film Transistors Y1 - 2020 VL - 95 IS - 2 SP - 861 ER - TY - JOUR A1 - Wang, L. A1 - Fjeldly, T.A. A1 - Iniguez, B. A1 - Slade, Holly C. A1 - Shur, M.S. T1 - Self-heating and kink effects in a-Si:H thin film transistors JF - IEEE Transactions on Electron Devices N2 - We describe a new physics based, analytical DC model accounting for short channel effects for hydrogenated amorphous silicon (a-Si:H) thin film transistors (TFT's). This model is based on the long channel device model. Two important short-channel phenomena, self-heating and kink effects, are analyzed in detail. For the self-heating effect, a thermal kinetic analysis is carried out and a physical model and an equivalent circuit are used to estimate the thermal resistance of the device. In deriving the analytical model for self-heating effect, a first order approximation and self-consistency are used to give an iteration-free model accurate for a temperature rise of up to 100/spl deg/C. In the modeling of the kink effects, a semi-empirical approach is used based on the physics involved. The combined model accurately reproduces the DC characteristics of a-Si:H TFT's with a gate length of the 4 /spl mu/m. Predictions for a-Si:H TFT's scaled down to 1 /spl mu/m are also provided. The model is suitable for use in device and circuit simulators. KW - Amorphous semiconductors Y1 - 2020 UR - https://doi.org/10.1109/16.822285 VL - 47 IS - 2 SP - 387 EP - 397 ER - TY - JOUR A1 - Slade, Holly C. A1 - Shur, M.S. T1 - Analysis of bias stress on unpassivated hydrogenated amorphous silicon thin-film transistors JF - IEEE Transactions on Electron Devices N2 - Both the subthreshold slope and the threshold voltage in inverted-staggered amorphous silicon thin-film transistors (a-Si:H TFTs) are vulnerable to metastable changes in the density of states (DOS) due to Fermi level displacement. In previous work, we have used passivated and unpassivated TFTs to distinguish between the effects of bulk states and interface states at the top passivating nitride interface. Here we report the results of experimental measurements and two-dimensional (2-D) simulations on unpassivated TFTs. Since there are no top interface states, all the observed changes are due solely to the bulk DOS. The subthreshold current activation energies in a-Si:H TFTs are compared for n-channel nonpassivated TFTs before and after bias stress. The experimental results agree well with the 2-D simulations, confirming that the dependence of subthreshold current activation energy on gate bias reveals the distribution of the DOS in energy but cannot resolve the magnitude of features in the DOS. This type of analysis is not accurate for TFTs with a top passivating nitride, since the activation energies in such devices are affected by the interfere states. KW - Stress KW - Amorphous materials KW - Thin film transistors KW - Interface states KW - Subthreshold current KW - Threshold voltage KW - Amorphous silicon KW - Metastasis KW - Two dimensional displays KW - Energy resolution Y1 - 2020 UR - https://doi.org/10.1109/16.701487 VL - 45 IS - 7 SP - 1548 EP - 1553 ER - TY - JOUR A1 - Shur, M.S. A1 - Slade, Holly C. A1 - Jacunski, M.D. A1 - Owusu, A.A. A1 - Ytterdal, T. T1 - SPICE Models for Amorphous Silicon and Polysilicon Thin Film Transistors JF - Journal of The Electrochemical Society N2 - We describe physically based analytical models for n‐channel amorphous silicon thin film transistors and for n‐ and p‐channel polysilicon thin film transistors. The models cover all regimes of transistor operation: leakage, subthreshold, above‐threshold conduction, and the kink regime in polysilicon thin film transistors. The models contain a minimum number of parameters which are easily extracted and can be readily related to the structural and material properties of the thin film transistors. The models have been verified for a large number of devices to scale properly with device geometry. KW - Thin Film Transistors Y1 - 2020 N1 - Invited paper: Elec. Chem. Soc. Proc.(October 1996) VL - 144 IS - 8 SP - 2833 EP - 2839 ER - TY - JOUR A1 - Shur, M.S. A1 - Jacunski, M. A1 - Slade, Holly C. A1 - Hack, M. T1 - Analytical Models for Amorphous Silicon and Polysilicon TFTs for High Definition Display Technology JF - Journal of the Society for Information Display KW - Thin Film Transistors Y1 - 2020 VL - 3 IS - 4 SP - 223 ER - TY - CHAP A1 - Iniguez, B. A1 - Wang, L. A1 - Fjeldly, T. A1 - Shur, M.S. A1 - Slade, Holly C. T1 - Thermal, Self-Heating and Kink Effects in a-Si:H Thin Film Transistors T2 - IEDM Technical Digest KW - Thin Film Transistors Y1 - 2020 ER - TY - CHAP A1 - Slade, Holly C. T1 - Characterization and Modeling of Frequency Dispersion in Amorphous Silicon Thin Film Transistors T2 - Materials Research Society, Proceedings, Amorphous Silicon Technology KW - Thin Film Transistors Y1 - 2020 ER - TY - CHAP A1 - Shur, M.S. A1 - Slade, Holly C. A1 - Ytterdal, T. A1 - Wang, L. A1 - Xu, Z. A1 - Aflatooni, K. A1 - Byun, Y. A1 - Chen, Y. A1 - Froggatt, M. A1 - Krishnan, A. A1 - Mei, P. A1 - Meiling, H. A1 - Min, B.-H. A1 - Nathan, A. A1 - Sherman, S. A1 - Stewart, M. A1 - Theiss, S.D. T1 - Modeling and Scaling of a-Si:H and poly-Si Thin Film Transistors T2 - Materials Research Society, Proceedings, Amorphous Silicon Technology KW - Thin Film Transistors Y1 - 2020 N1 - Invited paper ER - TY - CHAP A1 - Slade, Holly C. A1 - Shur, M.S. A1 - Hack, M. T1 - Temperature and Frequency Dependent Characteristics of Amorphous Silicon Thin Film Transistors T2 - Materials Research Society Proceedings, Amorphous Silicon Technology KW - Thin Film Transistors Y1 - 2020 VL - 377 SP - 725 ER - TY - CHAP A1 - Slade, Holly C. A1 - Globus, T. A1 - Gelmont, B. A1 - Shur, M.S. A1 - Hack, M. T1 - Effects of Stress on the Density of States in Amorphous Silicon TFTs T2 - Electrochemical Society Proceedings, Thin Film Transistors II KW - Thin Film Transistors Y1 - 2020 VL - 94 IS - 35 SP - 207 ER - TY - CHAP A1 - Globus, T. A1 - Slade, Holly C. A1 - Shur, M.S. A1 - Hack, M. T1 - Density of Deep Bandgap States in Amorphous Silicon from the Temperature Dependencies of Thin Film Transistor Current T2 - Materials Research Society Proceedings, Amorphous Silicon Technology KW - Thin Film Transistor Y1 - 2020 VL - 336 SP - 823 ER -