Transparent electronics is today one of the most advanced topics for a wide range of device applications. The key components are wide bandgap semiconductors, where oxides of different origins play an important role, not only as passive component but also as active component, similar to what is observed in conventional semiconductors like silicon. Transparent electronics has gained special attention during the last few years and is today established as one of the most promising technologies for leading the next generation of flat panel display due to its excellent electronic performance. In this paper the recent progress in n- and p-type oxide based thin-film transistors (TFT) is reviewed, with special emphasis on solution-processed and p-type, and the major milestones already achieved with this emerging and very promising technology are summarizeed. After a short introduction where the main advantages of these semiconductors are presented, as well as the industry expectations, the beautiful history of TFTs is revisited, including the main landmarks in the last 80 years, finishing by referring to some papers that have played an important role in shaping transparent electronics. Then, an overview is presented of state of the art n-type TFTs processed by physical vapour deposition methods, and finally one of the most exciting, promising, and low cost but powerful technologies is discussed: solution-processed oxide TFTs. Moreover, a more detailed focus analysis will be given concerning p-type oxide TFTs, mainly centred on two of the most promising semiconductor candidates: copper oxide and tin oxide. The most recent data related to the production of complementary metal oxide semiconductor (CMOS) devices based on n- and p-type oxide TFT is also be presented. The last topic of this review is devoted to some emerging applications, finalizing with the main conclusions. Related work that originated at CENIMAT|I3N during the last six years is included in more detail, which has led to the fabrication of high performance n- and p-type oxide transistors as well as the fabrication of CMOS devices with and on paper.

Oxide Semiconductor Thin‐Film Transistors: A Review of Recent Advances

Review of recent developments in amorphous oxide semiconductor thin-film transistor devices

Recent advances in flexible and stretchable electronics (FSE), a technology diverging from the conventional rigid silicon technology, have stimulated fundamental scientific and technological research efforts. FSE aims at enabling disruptive applications such as flexible displays, wearable sensors, printed RFID tags on packaging, electronics on skin/organs, and Internet-of-things as well as possibly reducing the cost of electronic device fabrication. Thus, the key materials components of electronics, the semiconductor, the dielectric, and the conductor as well as the passive (substrate, planarization, passivation, and encapsulation layers) must exhibit electrical performance and mechanical properties compatible with FSE components and products. In this review, we summarize and analyze recent advances in materials concepts as well as in thin-film fabrication techniques for high-k (or high-capacitance) gate dielectrics when integrated with FSE-compatible semiconductors such as organics, metal oxides, quantum...

High- k Gate Dielectrics for Emerging Flexible and Stretchable Electronics

radio-frequency identifi cation (RFID) tags, [ 4,5 ] and biosensors. [ 6,7 ] OTFTs usually exhibit very low switching speed and are diffi cult to use instead of inorganic thin-fi lm transistors (TFTs), although they possess the merits of fl exibility and low cost. Several challenges for OTFTs of large area are high fi eld-effect mobility ( μ FE ), low operating voltage, and solution processing. The μ FE value and operating voltage of pentacene OTFTs strongly depend on the gate dielectric material. [ 8–10 ]

Flexible organic thin-film transistors with silk fibroin as the gate dielectric.

Electronic Defects in Amorphous Oxide Semiconductors: A Review

We have investigated the high-performance oxide thin-film transistor (TFT) with an amorphous indium gallium zinc oxide (a-IGZO) channel and ZrO2 gate dielectrics. The a-IGZO TFT is fully fabricated at room temperature without any thermal treatments. ZrO2 is one of the most promising high-k materials. The a-IGZO TFT (channel W/L = 240/30 ?m) with ZrO2 shows high performance such as high on current of 2.11 mA and high field effect mobility of 28 cm2/(V·s) at the gate voltage 10 V. The threshold voltage and the subthreshold swing are 3.2 V and 0.56 V/decade, respectively. Note that the high-performance a-IGZO TFT is higher than ever shown in previous researches.

High-Performance a-IGZO TFT With $\hbox{ZrO}_{2}$ Gate Dielectric Fabricated at Room Temperature

Role of high-k gate insulators for oxide thin film transistors

We demonstrate the influence of the contact resistance on the electrical properties of a-IGZO thin-film transistors (TFTs) with ZrO 2 gate insulator grown by rf-magnetron sputtering at room temperature by adopting various channel widths and lengths. These TFTs have all been processed at room temperature with the same channel W/L ratio (W/L = 5) but different channel widths (50, 150, 250, and 350 μm). As the channel width increases from 50 to 350 μm, the on-current and field effect mobility increase from 0.7 to 1 mA and 19 to 31 cm 2 /V s, respectively. However, the subthreshold swing decreases from 0.37 to 0.19 V/decade. These results show that the contact resistance strongly affects the device performances and should be considered in these applications.

Systematic investigation on the effect of contact resistance on the performance of a‐IGZO thin‐film transistors with various geometries of electrodes

We investigated a-IGZO TFT with ZrO2 gate-dielectric having high on-current. High-capacitance is necessary to lead high on-current. Among many candidates, ZrO2 which is one of the most promising high-k materials has high capacitance originated high dielectric constant. We fabricated a-IGZO TFTs with ZrO2 gate-dielectric and analyzed electrical performances. Especially much higher mobility of 26 cm2/Vs and on-current of ∼6 mA than reported in other previous work are obtained. Also the threshold voltage (Vth), the on-to-off current ratio and the subthreshold swing are obtained of 3.6 V, of 9.6 × 106 and 0.6 V/decade, respectively.

P-23: High On-Current a-IGZO TFT

The TFTs have been fabricated with 3 different geometry SID electrodes which have the same channel W/L ratio (W/L

Jae Sang Lee

Papers

High-Performance a-IGZO TFT With $\hbox{ZrO}_{2}$ Gate Dielectric Fabricated at Room Temperature

Role of high-k gate insulators for oxide thin film transistors

Systematic investigation on the effect of contact resistance on the performance of a‐IGZO thin‐film transistors with various geometries of electrodes

P-23: High On-Current a-IGZO TFT

Study on Contact Resistance on the Performance of Oxide Thin Film Transistors