Fabrication of High-Performance ZnO Thin-Film Transistors With Submicrometer Channel Length

IEEE J. Electron Devices Soc.

Huang

2015

By virtue of the film-profile engineering scheme and properly designed device structure, ZnO TFTs with discrete bottom gates and sub-micron channels were fabricated and characterized. In the fabrication, a suspended bridge constructed over the bottom gate is used to tailor the profile of subsequently deposited films. Superior electrical characteristics in terms of ultrahigh ON/OFF current ratio (∼10 10 ), steep sub-threshold swing (66∼108 mV/dec), and very low off-state leakage current are demonstrated with the fabricated devices. Effects of channel lengths on the device characteristics are also explored. Because of more effective shadowing of the depositing species with a longer suspended bridge, the deposited films become thinner at the central channel. As a result, the device shows more positive turn-on voltage and better subthreshold swing with increasing channel length.INDEX TERMS Metal oxide, film profile engineering (FPE), ZnO, thin-film transistor.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fabrication and Characterization of Film Profile Engineered ZnO TFTs With Discrete Gates

Lyu

IEEE J. Electron Devices Soc.

Huang

2015

“…10 Owing to the unique deposition conditions of several tools, this technique can be implemented to deposit films with desired profiles. In this study, we aim to develop the proposed FPE concept with the modified deposition pressure of evaporator systems to fabricate high-performance OTFTs with submicron channel length and address the above mentioned issues in the earlier work.…”

mentioning

confidence: 99%

“…In the previous report on the fabrication of ZnO TFTs with the FPE scheme, 10 an RF magnetron sputter was used to deposit the continuous and highly concave channel film beneath the suspended bridge built over the center of the device. In this study, a thermal evaporator was employed for depositing the pentacene channel and a major consideration on the deposition pressure is raised.…”

mentioning

confidence: 99%

Submicron organic thin-film transistors fabricated by film profile engineering method

Lin²,

Applied Physics Letters

et al. 2014

Self Cite

In this work, we explore and demonstrate the feasibility of a film profile engineering (FPE) concept in fabricating pentacene-based organic thin-film transistors (OTFTs) with submicron channel length. The FPE scheme utilizes a suspended bridge built on the wafer and the specific deposition conditions to form thin films with desirable profiles. In order to form a continuous pentacene channel under the bridge, the background pressure of thermal evaporator is adjusted by pumping down the filling N2 to a specific level. The results show that, by setting the deposition pressure at 3 mtorr, functional operations of OTFTs with channel length ranging from 0.4 to 0.6 μm are obtained.

“…Recently, we developed a film-profile-engineering (FPE) scheme [10], [11] for fabrication of high-performance metaloxide TFTs. Principles of the FPE methods are to deposit the major thin films, e.g., gate dielectric, channel, and source/drain (S/D) metal contacts, in a device with desirable profiles.…”

mentioning

confidence: 99%

Effects of Gate Dielectric and Process Treatments on the Electrical Characteristics of IGZO TFTs With Film Profile Engineering

Shie

IEEE Trans. Plasma Sci.

Lyu

et al. 2014

Self Cite

In this paper, high-performance InGaZnO (IGZO) thin-film transistors were fabricated with film-profile-engineering scheme. The impacts of gate dielectric, O 2 /Ar ratio during the sputtering of the IGZO, and annealing ambient on the device performance were investigated. It is found that the turn-ON voltage of the device is closely related to the gate dielectric material. For the devices with Al 2 O 3 as the gate dielectric, decent performance in terms of high ON/ OFF current ratio (>10 8 ), extremely steep subthreshold swing (62 mV/decade), and good mobility (19.8 cm 2 /V·s) is obtained. The influences of O 2 /Ar flow ratio are distinct for the devices with Al 2 O 3 gate oxide. Significant improvement in the stability of the devices to the environment is achieved with the anneal done in a low-pressure N 2 ambient. Index Terms-Film profile engineering (FPE), InGaZnO (IGZO), metal oxide, thin-film transistors (TFTs).