具有加厚源/汲極與薄通道之新穎低溫複晶矽薄膜電晶體之製作與特性研究

Abstract

本篇論文中，我們將探討和比較所製作的新穎結構，此新穎結構具有加厚的汲/源極和一個薄通道，因加厚的汲/源極和薄通道帶來的效應，我們可以增大導通狀態時的電流以及降低漏電流，進而改善我們的開/關電流的比值至107，且更可以抑制扭節現象 (kink effect) 的產生，而不需要在製程中多出一道額外的光罩。在我們的研究中，將新結構與傳統結構相比，開/關電流比在汲極電壓為5V時，將會從6*106增加到3.5*107。此新穎結構的各種尺寸也具備不錯的對稱性。此外我們還探討了閘極下方與汲/源極重疊處對元件特性的影響，我們認為此區較小會獲得較佳之電性。

In this thesis, the characteristics of the novel structure of poly-Si TFTs with thick S/D and thin channel have been investigated and compared. With the thick S/D and thin channel, we can not only decrease the off-state current but also increase the on-state current. Therefore, we succeed to achieve the on/off ratio about 7 orders and substantially suppress the kink effect without an extra mask. In our study, the on/off ratio is rose from 6*106 to 3.5*107 for Vds = 5V, W/L = 50 μm/10 μm. We also have a great symmetry for four device sizes of our novel structure of LTPS TFTs. In our experiment, we also investigated the influence of different gate-overlap region, we have shown the smaller gate-overlap region would be more better.