5.8‐inch QHD flexible AMOLED display with enhanced bendability of LTPS TFTs

By applying the curve-type TFT with longitudinal strain, TFT parameters do change little down to the 2R bending. The mobility variation range reduces down to 4% compared with 28% of the line-type channel with transverse strain. The smaller variation is preferred for a high quality display. We clarified that majority carrier’s effective mass and scattering rate are dominant factors influencing the bended TFT's performance, which can be controlled by the strain orientation and channel shape. These understanding and improvement was embedded in the 5.8" flexible QHD AMOLED panel with multi edge curvature of Galaxy S8. Through this achievement, we made our flexible premium AMOLED panels more performable, reliable and highly productive in small R bending circumstance. Author

[1]  Chenxu Zhao,et al.  Micro-Raman spectroscopy analysis of residual stress in polysilicon MEMS resonators , 2013, The 8th Annual IEEE International Conference on Nano/Micro Engineered and Molecular Systems.

[2]  Mobility Modeling in a p-MOSFET under Uniaxial Stress , 2011 .

[3]  S. Thompson,et al.  Uniaxial-process-induced strained-Si: extending the CMOS roadmap , 2006, IEEE Transactions on Electron Devices.

[4]  Z. Suo,et al.  Mechanics of rollable and foldable film-on-foil electronics , 1999 .

[5]  Peyman Servati,et al.  Functional Pixel Circuits for Elastic AMOLED Displays , 2005, Proceedings of the IEEE.

[6]  M. Bohr,et al.  A logic nanotechnology featuring strained-silicon , 2004, IEEE Electron Device Letters.

[7]  A. Dimoulas,et al.  Advanced Gate Stacks for High-Mobility Semiconductors , 2007 .

[8]  M. Lee,et al.  Strained Si, SiGe, and Ge channels for high-mobility metal-oxide-semiconductor field-effect transistors , 2005 .

[9]  J. Swart,et al.  Micro-Raman stress characterization of polycrystalline silicon films grown at high temperature , 2004 .

[10]  C.-Y. Peng,et al.  Mechanical strain effect of n-channel polycrystalline silicon thin-film transistors , 2006 .

[11]  A. Toriumi,et al.  In-plane mobility anisotropy and universality under uni-axial strains in nand p-MOS inversion layers on (100), [110], and (111) Si , 2004, IEDM Technical Digest. IEEE International Electron Devices Meeting, 2004..

[12]  K. Saraswat,et al.  Physical mechanisms of electron mobility enhancement in uniaxial stressed MOSFETs and impact of uniaxial stress engineering in ballistic regime , 2005, IEEE InternationalElectron Devices Meeting, 2005. IEDM Technical Digest..

[13]  A. Hara,et al.  Oriented Lateral Growth and Defects in Polycrystalline-Silicon Thin Films on Glass Substrates , 2012 .

[14]  T. Saraya,et al.  Physical understandings of si (110) hole mobility in ultra-thin body pFETs by ≪110≫ and ≪111≫ uniaxial compressive strain , 2009, 2009 IEEE International Electron Devices Meeting (IEDM).

[15]  S. Thompson,et al.  Physics of strain effects in semiconductors and metal-oxide-semiconductor field-effect transistors , 2007 .

[16]  S. Thompson,et al.  Key differences for process-induced uniaxial vs. substrate-induced biaxial stressed Si and Ge channel MOSFETs , 2004, IEDM Technical Digest. IEEE International Electron Devices Meeting, 2004..

[17]  Modeling of some electrical parameters of a MOSFET under applied uniaxial stress , 2011 .

[18]  K. Kitahara,et al.  Characterization of Defects and Stress in Polycrystalline Silicon Thin Films on Glass Substrates by Raman Microscopy , 2011 .

[19]  S. Takagi.  Strained-Si CMOS Technology , 2007 .

[20]  O. Weber,et al.  Examination of Additive Mobility Enhancements for Uniaxial Stress Combined with Biaxially Strained Si, Biaxially Strained SiGe and Ge Channel MOSFETs , 2007, 2007 IEEE International Electron Devices Meeting.