The Structure of Hydrogenated Microcrystalline Silicon (μc-Si:H) TFTs Deposited by PECVD

• Main Authors: Yao-Hong Chien, 簡耀黌
• Other Authors: Wu-Yi Uen
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/23032740130974652463

碩士 === 中原大學 === 電子工程研究所 === 95 === The hydrogenated microcrystalline silicon (μc-Si:H) TFTs are prepared by plasma-enhanced chemical vapor deposition(PECVD) with the controlling factors of these experiments including 0.5% SiH4/H2 gas flow rate, 1,500W RF power, 650Pa pressure, and 3000sccm Ar carrier gas, respectively. The surface morphology of μc-Si:H thin film after secco etching is observed by SEM(Scanning Electron Microscope) and AFM(Atomic Force Microscope), and grain size is about 20-30nm. The high resolution transmission electron microscopy (HRTEM) image of the cross section of μc-Si:H TFTs deposited on glass substrate. It is shown the clearly difference of the inverted taper structure between the microcrystalline silicon and buffer layer interfaces. Raman spectra is shown that under different deposition environment, there is less for the μc-Si:H layer deposited by PECVD than poly-Si although the intensity ratio of the peak(~517cm-1) shows clear variation. The behavior of the threshold voltage and field-effect mobility of μc-Si:H TFTs under the bias gate stress, light illuminated and thermal stress experiments indicates unobvious difference to the a-Si:H TFTs. The crystallized distribution proved that the transistor channel was the amorphous state including most dangling bonds. To adopt the top-gate structure μc-Si:H TFTs to test, we will get better transistor properties.