Effects of electro-mechanical stressing on the electrical characterization of on-plastic a-Si:H thin film transistors
Journal
Materials Research Society Symposium
Journal Volume
1153
Pages
417-422
ISBN
9781605111261
Date Issued
2009
Author(s)
Abstract
We analyzed the effect of electromechanical stressing on the electrical characteristics of hydrogenated amorphous silicon thin-film transistors. It had been shown that the TFTs, fabricated at 150 ¢XC, respond to tension/compression by a rise/fall in electron mobility. In TFTs fabricated using the same process, a slight shift of threshold voltage was observed under prolonged high compressive strain and the gate leakage current slightly increases after ?2% compressive strain. In general, the change of TFT performance due to pure mechanical straining is small in comparison to electrical gate-bias stressing. From the comparison among Maxwell stress (induced by electrical gate-bias stressing), mechanical stress (applied by bending), and drifting electrical force for passivated hydrogen atom, the most significant cause for the change of electrical characterization of a-Si:H TFTs should be the trapping charges inside the dielectric, under combined electrical and mechanical stressing. The mechanical stress does not act on Si-H bonds to drift hydrogen atoms, while it is mainly balanced by the rigid Si-Si networks in a-Si:H or a-SiNx. Therefore, mechanical stress has very little effect on the instability of low temperature processed a-Si:H TFTs. ? 2009 Materials Research Society.
Type
conference paper