Title :
Structure-Dependent Contact Barrier Effects in Bottom-Contact Organic Thin-Film Transistors
Author :
Feng, Linrun ; Xu, Xiaoli ; Guo, Xiaojun
Author_Institution :
Dept. of Electron. Eng., Shanghai Jiao Tong Univ., Shanghai, China
Abstract :
This paper investigates and compares the structure-dependent contact barrier effects on the electrical performance of two bottom-contact (BC) structure (staggered and inverted coplanar) organic thin-film transistors (OTFTs) by numerical simulations. The drain saturation current (Idsat) of the staggered device is found to be more sensitive to the variation of the source/drain (S/D) electrode thickness than that of the inverted coplanar one. The inverted coplanar device shows stronger dependence of Idsat on the contact barrier than the staggered device, and the dependence is also much more affected by the step coverage profile of the semiconductor layer on top of the S/D electrodes. For the inverted coplanar structure OTFTs, a steeper step coverage profile and a lower contact barrier can help to achieve better tolerance of Idsat to the variations of the contact barrier and step profile, respectively. The gate structure (self-aligned or fully covered) does not show any influence. The study forms a clear understanding of the device-structure-dependent carrier transport mechanisms in BC OTFTs and could also provide important guidelines for optimal device structure design and related process development for BC OTFTs.
Keywords :
Schottky barriers; organic semiconductors; thin film transistors; bottom contact organic thin film transistors; carrier transport mechanisms; drain saturation current; electrical performance; gate structure; inverted coplanar device; source-drain electrode thickness; step coverage profile; structure dependent contact barrier effects; Contacts; Dielectrics; Electrodes; Logic gates; Organic thin film transistors; Contact barrier; Schottky contact; inverted coplanar; organic thin-film transistor (OTFT); staggered;
Journal_Title :
Electron Devices, IEEE Transactions on
DOI :
10.1109/TED.2012.2219052