Analysis of self-heating related instability in n-channel polysilicon thin film transistors fabricated on polyimide

• Published in: Thin solid films 2009-10, Vol.517 (23), p.6371-6374
• Main Authors: Maiolo, L., Cuscunà, M., Mariucci, L., Minotti, A., Pecora, A., Simeone, D., Valletta, A., Fortunato, G.
• Format: Article
• Language: English
• Subjects: Applied sciences; Electronics; Exact sciences and technology; Polyimide; Polysilicon TFTs; Self-heating instability; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Transistors
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2009.02.105

In this work, we investigated self-heating related instability in polysilicon thin film transistors (poly-Si TFTs) fabricated on polyimide (PI) substrates. Indeed, when Joule heating becomes relevant, the temperature of the active layer can substantially rise, since the devices are fabricated on thermally insulating substrates. As a result, electrical instability is triggered and attributed to the generation of interface states, due to the Si–H bond breaking, and charge trapping into the gate insulator. In addition, by using 3-dimensional numerical simulations, coupling the thermodynamic and transport models, we analyzed the temperature distribution of the device under operating conditions and found that self-heating is more severe for devices fabricated on plastic substrates.