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Proceedings Paper

The geometry effect on threshold voltage of top-contact and bottom contact pentacene based thin film transistors
Author(s): Yu-Wu Wang; De-Zhi Liu; Ming-Yue Hong; Horng-Long Cheng
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Paper Abstract

In this article, we fabricated a series of different geometries for pentacene based thin film transistors (TFTs), including top contact (TC) and bottom contact (BC) configurations, to monitor variations in characteristics. The threshold voltage (Vth) in the saturation regime shifted toward a positive voltage, i.e., from 0.5, 3.2, 9.1, 12.1, and 19.5 V for the channel lengths 67, 47, 23, 19, and 15 μm, respectively, in BC TFTs. All of the TFTs were operated in depletion mode. However, the Vth in the linear regime shifted from -9.3, -9.0, -3.8, -1.8, and 1.5 V for the same devices. Most of the TFTs in the linear regime were operated in enhanced mode. The phenomenon is believed to be strongly correlated with the longitudinal electric field (VDS/L). The high VDS induces a high carrier injection, which makes the pentacene TFTs behave like a depletion type transistor. This assumption is evidenced by the low carrier injection with small VDS results. The device configuration and space charge region must be discussed in more detail. Furthermore, the field effect mobility variation and structure configuration effect is discussed in more detail within the full manuscript.

Paper Details

Date Published: 21 August 2009
PDF: 8 pages
Proc. SPIE 7417, Organic Field-Effect Transistors VIII, 74171F (21 August 2009); doi: 10.1117/12.826072
Show Author Affiliations
Yu-Wu Wang, National Changhua Univ. of Education (Taiwan)
De-Zhi Liu, National Changhua Univ. of Education (Taiwan)
Ming-Yue Hong, National Changhua Univ. of Education (Taiwan)
Horng-Long Cheng, National Cheng Kung Univ. (Taiwan)


Published in SPIE Proceedings Vol. 7417:
Organic Field-Effect Transistors VIII
Zhenan Bao; Iain McCulloch, Editor(s)

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