The effects of microcrystalline silicon film structure on low-high-low band-gap thin film transistor

• Published in: Materials chemistry and physics 2000-01, Vol.62 (2), p.153-157
• Main Authors: Chang, Chun-Yen, Lee, Yeong-Shyang, Huang, Tiao-Yuan, Shih, Po-Sheng, Lin, Chiung-Wei
• Format: Article
• Language: English
• Subjects: Amorphous; Applied sciences; Bipolar transistors; Crystalline factor; Electronics; Exact sciences and technology; Microcrystalline; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Thin-film transistor (TFT); Transistors
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/S0254-0584(99)00174-1

The effects of hydrogenated microcrystalline silicon (μc-Si:H) film with various crystalline factors on thin-film transistors (TFTs) with low-high-low band gap structure are studied. Compared to hydrogenated amorphous silicon (a-Si:H) TFT with conventional inverted-stagger structure, the device with μc-Si:H film of high crystalline factor in the active channel depicts improved interfacial active layer near the gate insulator interface as well as the later-grown bulk active layer, resulting in improved device parameters including field effect mobility, threshold voltage, subthreshold swing and ON-current. While a-Si:H film of low crystalline factor and high-band-gap is proposed for the source and drain offset regions in the new device to prevent the band-to-band tunneling, thus alleviates the high OFF-current inherent in conventional μc-Si:H thin-film transistors, resulting in an improved ON/OFF current ratio.