Pentacene Thin Film Transistors and Circuits: Influence of Processing and Device Design

2002 ◽  
Vol 725 ◽  
Author(s):  
D. Knipp ◽  
R. A. Street ◽  
B. Krusor ◽  
J. HO

AbstractThe influence of different dielectrics on the structural and electronic properties of pentacene films and TFTs is discussed. The pentacene films were thermally evaporated on inorganic dielectrics compatible with flexible substrates. A strong correlation between morphology and structural properties of the pentacene films and the mobility of the TFTs was observed for all the dielectrics studied. In the case of plasma enhanced chemical vapor deposited (PECVD) silicon nitride and silicon oxide dielectrics the growth of pentacene is mainly determined by the roughness of the dielectric. The roughness inhibits the ordering of pentacene molecules on the surface. However, by optimizing the fabrication process of the dielectrics, we have achieved similar pentacene mobilities on PECVD dielectrics and thermal oxide (0.4 cm2/Vs), without employing self-assembled monolayers like octadecyltrichlorosilane (OTS). An OTS treatment of oxide based dielectrics leads to an increase of the mobility by a factor of 2-3 up to >1cm2/Vs for thermal oxide. Pentacene films on inorganic dielectrics exhibit mobilities from of 0.2-1.2 cm2/Vs and high on/off ratios between 107 and 108.

2011 ◽  
Vol 1287 ◽  
Author(s):  
Anupama Mallikarjunan ◽  
Laura M Matz ◽  
Andrew D Johnson ◽  
Raymond N Vrtis ◽  
Manchao Xiao ◽  
...  

ABSTRACTThe electrical and physical quality of gate and passivation dielectrics significantly impacts the device performance of thin film transistors (TFTs). The passivation dielectric also needs to act as a barrier to protect the TFT device. As low temperature TFT processing becomes a requirement for novel applications and plastic substrates, there is a need for materials innovation that enables high quality plasma enhanced chemical vapor deposition (PECVD) gate dielectric deposition. In this context, this paper discusses structure-property relationships and strategies for precursor development in silicon nitride, silicon oxycarbide (SiOC) and silicon oxide films. Experiments with passivation SiOC films demonstrate the benefit of a superior precursor (LkB-500) and standard process optimization to enable lower temperature depositions. For gate SiO2 deposition (that are used with polysilicon TFTs for example), organosilicon precursors containing different types and amounts of Si, C, O and H bonding were experimentally compared to the industry standard TEOS (tetraethoxysilane) at different process conditions and temperatures. Major differences were identified in film quality especially wet etch rate or WER (correlating to film density) and dielectric constant (k) values (correlating to moisture absorption). Gate quality SiO2 films can be deposited by choosing precursors that can minimize residual Si-OH groups and enable higher density stable moisture-free films. For e.g., the optimized precursor AP-LTO® 770 is clearly better than TEOS for low temperature PECVD depositions based on density, WER, k charge density (measured by flatband voltage or Vfb); and leakage and breakdown voltage (Vbd) measurements. The design and development of such novel precursors is a key factor to successfully enable manufacturing of advanced low temperature processed devices.


2014 ◽  
Vol 104 (5) ◽  
pp. 051607 ◽  
Author(s):  
Peng Xiao ◽  
Linfeng Lan ◽  
Ting Dong ◽  
Zhenguo Lin ◽  
Wen Shi ◽  
...  

1997 ◽  
Vol 500 ◽  
Author(s):  
Toshiaki Arai ◽  
Hideo Iiyori

ABSTRACTNovel anodized films of nitrogen-added aluminum-based alloys were proposed for use in the fabrication of gate insulators for thin-film transistors, and the effect of nitrogen addition on the anodized aluminum-based alloys was investigated. Gadolinium and neodymium were employed as alternative alloy components. The film thickness, the dielectric constant, and the roughness average of the anodized films decreased as the nitrogen content increased, and the nitrogen content was required to be lower than 20 at.%. The most improved values of the breakdown electric fields of anodized aluminum-gadolinium and aluminum-neodymium alloy were 10.1 MV/cm with 6.0 at.% nitrogen content and 9.9 MV/cm with 4.0 at.% nitrogen content, respectively. The leakage currents of the anodized films under a negative bias, which could not be suppressed by high-temperature annealing, were adequately suppressed by nitrogen addition, especially in anodized aluminum-gadolinium alloy. The current leakage of the anodized aluminum-gadolinium alloy with 6.0 at.% nitrogen content became -8E-13 A at -10 V and 150°C. This value is nearly equal to that of chemical-vapor-deposited (CVD) films.


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