CDT in Collaboration with SILVACO Develops a New Universal Organic Thin Film Transistor (UOTFT) Model

CAMBRIDGE, United Kingdom, 20th August, 2008 - Cambridge Display Technology is pleased to announce that in collaboration with SILVACO Data Systems, they have developed a new Universal Organic Thin Film Transistor (UOTFT) SPICE model. Circuit designers can now design and simulate circuits using OTFT (organic thin film transistor) technology. This is an important step forward in promoting the future use of OTFT technology.

The rapid development of organic electronics is mainly driven by applications that require low cost electronic circuits covering large areas with mechanical flexibility. Examples are: e-skin, e-paper, e-nose, smart-fabrics, flexible displays, printed electronics or radio frequency identification tags (RFID). OTFTs form the basis of future organic electronic circuits.

The model is implemented in Simucad SmartSpice, a leading analog circuit simulator.

The UOTFT SPICE model combines universal charge-based field effect transistor modeling with OTFT specific channel charge, mobility bias, temperature dependences, and nonlinear contact resistances. This combination maximizes UOTFT generic modeling capabilities, and makes it suitable for a large variety of OTFT device architectures, material specifications, and fabrication technologies.

The design of organic electronics circuits depends on accurate and efficient OTFT compact models in commercial circuit simulation tools. A range of distinct features in OTFT device properties require special consideration and a different modeling approach compared to their inorganic counterparts. The most notable differences include a trap-assisted charge distribution and mobility behaviour, unipolar or bipolar charge accumulation operation mode and non-ohmic contact resistances. The existing MOSFET, as well as amorphous and poly-silicon TFT models, are therefore not suitable for the design of OTFT circuits.

David Fyfe, CEO of CDT stated "This activity will enable CDT to further develop its technology base in these new areas of organic semiconductor technology. We are delighted to be working with SILVACO on this project which will speed development and commercialisation of low cost rigid and flexible electronics applications of organic semiconductor technology".

The project is being part-funded by the UK government’s Technology Strategy Board and their Technologist for Electrical Systems, Mike Biddle commented: "We are very happy with the excellent progress made by this project, and to see that this new approach will soon be ready for commercial exploitation. This is a great example of world class businesses coming together in the UK to research and develop innovative technology that has global market potential."

“We are delighted to be working with a leading organic research company such as CDT, and the UK government, on such a cutting edge project,” said Dr Ivan Pesic, President and CEO of Simucad. “This new ground-breaking model will enable circuit designers to accurately simulate the next generation of organic circuits. We look forward to continuing this partnership on future projects.”


About CDT
Cambridge Display Technology (CDT), headquartered at Cambourne near Cambridge in the UK, was spun out of Cambridge University in 1992 and acquired by Sumitomo Chemical, Japan in September 2007. Together CDT and Sumitomo lead the research and commercialisation of light emitting polymer technology used in displays and lighting applications. Devices incorporating this technology are often referred to as P-OLED, or polymer organic light emitting diode, devices. CDT holds an extensive patent and know-how portfolio relating to P-OLED materials and devices and actively licenses this portfolio to display and lighting companies around the world. CDT and Sumitomo engage in a wide range of Organic Electronics activities such as organic thin film transistor (OTFT). More information on CDT can be found at:

Alexandra Gay, Marketing and Communication Specialist
+44 1954 713600

About SILVACO International 
SILVACO International, headquartered in Santa Clara, California, is a leading vendor of TCAD and EDA software. Founded in 1984, and a TCAD leader since 1987, the company is privately held. In 2005 it spun out Simucad Design Automation which now focuses on EDA software. Worldwide customers include leading foundries, fabless semiconductor companies, integrated semiconductor manufacturers, and universities.

More information:

Ahmed Nejim
+44 (0) 1480 484400

About SIMUCAD Design Automation
Simucad Design Automation is a leading provider of simulation and CAD software tools used for developing analog, mixed-signal, and RF integrated circuits. Founded in 2004 as a spin-off from SILVACO International, the company delivers products for circuit simulation, custom IC layout and verification, interconnect modeling, digital simulation, and IP characterization. The company provides a complete PDK-based design flow with interfaces to third-party design platforms. Simucad has a worldwide presence inherited from SILVACO's twenty years of business and is preparing for an IPO. For more information about Simucad, please visit

Dr. Ivan Pesic
+1 (408) 567-1000