Device Modeling and Circuit Design for Organic Thin-film Transistors (OTFTs)

Course manager: Deyu Tu

Suggested credits: 6 hp

Aims

The research of organic electronics has been growing significantly in the last two decades. Organic Thin-film Transistors (OTFTs) are one of the most important devices in this area, which plays a key role in low-cost large-area electronics. This course aims at giving a general overview of state-of-the-art OTFTs and advanced knowledge of device modeling and circuit design with OTFTs for PhD students in related fields.

Organisation

The course consists of 10 lectures and is suggested to give 6 hp. Lectures are given by Deyu Tu. The course is open to all PhD students at Linköping University. The participants should have basic knowledge of semiconductors and electronics. Anyone interested in participation is welcome, please sign up via emailing Deyu Tu by March 23, 2015. The first lecture will be in Nollstället on March 25 2015, at 13:15. We will choose later dates at the first lecture, tentatively one lecture per week.

Literature

The course is based on multiple books, reviews, and recent research papers in related fields. Five books are recommended as course literature as follow:

• Semiconductor Devices: Physics and Technology, 3rd Edition, Simon M. Sze, Ming-Kwei Lee, John Wiley & Sons, Apr 23, 2012.
• Semiconductor Devices: Modelling and Technology, Nandita Dasgupta, Amitava Dasgupta, PHI Learning Pvt. Ltd., Jan 1, 2004.
• Organic Field-Effect Transistors, Zhenan Bao, Jason Locklin, CRC Press, May 17, 2007.
• Applications of Organic and Printed Electronics, Eugenio Cantatore, Springer Science & Business Media, Sep 19, 2012.
• Analog Organic Electronics, Hagen Marien, Michiel Steyaert, Paul Heremans, Springer Science & Business Media, Aug 1, 2012.

Examination

Five homework assignments and one presentation in literature reading.

Preliminary lecture plan

1. Introduction. A brief overview of organic electronics and organic thin-film transistors (OTFTs) is given in this lecture. In details, we will discuss the origination of organic electronics, the history of OTFTs, materials, processes, devices, applications, challenges, and a roadmap for organic and printed electronics.
2. Charge transport in disordered organic semiconductors. In this lecture, we summarize the charge transport theories that have been used to explain the electrical properties in disordered organic semiconductors. The low crystallinity due to the small interaction between the molecules is the main difference of disordered organic semiconductors from traditional inorganic crystalline semiconductors (Si, Ge, etc.)
3. Compact modeling (DC). The compact modeling is a key issue to efficient simulation for circuit design. We review existing compact models that describe DC behaviors of OTFTs, including parameter extraction and model optimization.
4. Compact modeling (Dynamic). We focus on compact models that describe transient/dynamic behaviors of OTFTs in this lecture. The models are based on terminal charges/capacitances in general.
5. Device variation modeling. Device variation is one of the main challenges for OTFTs. We present a summary of device variation models, mainly based on noise, hysteresis, bias stress, or device mismatch. Monte Carlo simulation in organic semiconductor is discussed in addition.
6. SPICE modeling and simulation. SPICE models for OTFTs are reviewed in this lecture, including MOSFET-based, a-Si TFT-based, black box, equivalent circuit, and physical-oriented compact models.
7. Digital circuits with OTFTs. Digital circuit functionality with OTFTs can be implemented in both static and dynamic logic. A number of existing ways to implement digital circuit blocks (inverters, logic gates, etc.) are reviewed in this lecture.
8. Analog circuits with OTFTs The design strategies for analog circuits with OTFTs are summarized and a few examples of analog building blocks (oscillators, amplifiers, charge pumps, ADC/DAC, etc.) are given in this lecture.
9. Circuit characterization and analysis. A variety of ways to characterize circuits with OTFTs are discussed, including robustness, timing, driving capability, power consumption, and so on. In addition, a full analysis flow for OTFT circuits is presented along with some novel analysis concepts.
10. Reliability and fault-tolerant design. We review popular fault-tolerant techniques including static (redundancy, NAND multiplexing) and dynamic (error-correction codes) and their possible application in OTFT circuits.