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Frontiers of Optoelectronics

Front. Optoelectron.    2015, Vol. 8 Issue (4) : 445-450     DOI: 10.1007/s12200-014-0451-1
RESEARCH ARTICLE |
Simulation study on the active layer thickness and the interface of a-IGZO-TFT with double active layers
Xiaoyue LI,Sheng YIN(),Dong XU
School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
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Abstract

In this paper, ATLAS 2D device simulator of SILVACO was used for device simulation of inverted-staggered thin film transistor using amorphous indium gallium zinc oxide as active layer (a-IGZO-TFT) with double active layers, based on the density of states (DOS) model of amorphous material. The change of device performance induced by the thickness variation of each active layer was studied, and the interface between double active layers was analyzed. The best performance was found when the interface was near the edge of the channel, by optimizing the thickness of each active layers, the high performance device of threshold voltage (Vth) = −0.89 V, sub-threshold swing (SS)= 0.27, on/off current ratio (ION/IOFF) = 6.98 × 1014 was obtained.

Keywords amorphous indium gallium zinc oxide (a-IGZO)      double active layers      interface      density of states (DOS)      ATLAS     
Corresponding Authors: Sheng YIN   
Just Accepted Date: 26 September 2014   Online First Date: 17 November 2014    Issue Date: 24 November 2015
 Cite this article:   
Xiaoyue LI,Sheng YIN,Dong XU. Simulation study on the active layer thickness and the interface of a-IGZO-TFT with double active layers[J]. Front. Optoelectron., 2015, 8(4): 445-450.
 URL:  
http://journal.hep.com.cn/foe/EN/10.1007/s12200-014-0451-1
http://journal.hep.com.cn/foe/EN/Y2015/V8/I4/445
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Xiaoyue LI
Sheng YIN
Dong XU
Fig.1  

Proposed density of states (DOS) model for a-IGZO. EC and EV are conduction and valence band edge energies, respectively. Solid curves within the bandgap represent the exponentially distributed band-tail states (gta, gtd), while the dash curve near the conduction band edge represents the Gaussian-distributed donor-like oxygen vacancy (OV) states (ggd)

Fig.2  

Schematic of the TFT structure we adopt in this paper

Fig.3  

Transfer characteristic curves of IGZO-TFT with different x (DL and SL represent double layers and single layer, respectively)

Fig.4  

Carrier distribution of carriers when −5 V gate voltage is applied

Fig.5  

Carrier distribution of carriers when 20 V gate voltage is applied

Tab.1  

Key simulation parameters of a-IGZO (based on Ref. [8])

Tab.2  

Electrical properties of each a-IGZO TFT with different x

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