Enhanced channel mobility in polysilicon thin film transistors
- 1 August 1994
- journal article
- Published by Institute of Electrical and Electronics Engineers (IEEE) in IEEE Electron Device Letters
- Vol. 15 (8) , 274-276
- https://doi.org/10.1109/55.296214
Abstract
Due to scattering by charged grain boundaries, carrier mobility /spl mu/ in the channel of polysilicon thin film transistors (TFT) is usually much lower than the bulk silicon value. We have studied a series of /sub p/-channel TFT devices with varying gate oxide thicknesses d/sub ox/ and found that CL shows a strong increase when d/sub ox/ is reduced below 150 /spl Aring/. We attribute this effect to the screening of the charged grain boundary by the gate conductor. The screening becomes effective when the characteristic length associated with the potential barrier at charged grain boundaries becomes comparable to the optical distance between the grain boundary charge and its mirror image in the gate electrode. From the known structure parameters the onset of the strong screening is estimated to occur at oxide thicknesses of about 100 /spl Aring/.Keywords
This publication has 7 references indexed in Scilit:
- Dependence of the off-state current in polycrystalline silicon thin film on electric field in the channelApplied Physics Letters, 1994
- Active-gate thin-film transistorIEEE Electron Device Letters, 1993
- A semi-empirical model for the field-effect mobility of hydrogenated polycrystalline-silicon MOSFETsIEEE Transactions on Electron Devices, 1988
- Characteristics of offset-structure polycrystalline-silicon thin-film transistorsIEEE Electron Device Letters, 1988
- Study of thermally oxidized yttrium films on siliconApplied Physics Letters, 1987
- Recrystallization of amorphized polycrystalline silicon films on SiO2: Temperature dependence of the crystallization parametersJournal of Applied Physics, 1987
- Modeling of accumulation-mode MOSFET's in PolySilicon thin filmsIEEE Electron Device Letters, 1985