A partnership between the Holst Centre, imec and Evonik has resulted in a general purpose 8bit microprocessor. The device has been made using complementary thin film transistors (TFTs) processed at temperatures compatible with plastic foil substrates (250°C).
The new 'hybrid' technology integrates two types of semiconductors – metal oxide for n-type TFTs and organic molecules for p-type TFTs – in a CMOS microprocessor circuit running at 2.1kHz. The partners describe the clock speed as 'unprecedented'.
The microprocessor consists of two chips – a processor core chip and a general purpose instruction generator (P2ROM). For the processor core chip, a complementary hybrid organic-oxide technology was used (p:n ratio 3:1). The n-type transistors are 250°C solution processed metal oxide TFTs with typically high charge carrier mobility (2cm2/Vs).
The p-type transistors are small molecule organic TFTs with mobility of up to 1cm2/Vs. Complementary logic allows for a more complex and complete standard cell library, including additional buffering in the core and the implementation of a mirror adder in the critical path.
The P2ROM is a one time programmable ROM configured using inkjet printing of a conductive silver ink. The chip – divided into a hybrid complementary part and a unipolar n-TFT part – can operate at frequencies up to 650Hz and from a Vdd of 10V.
Low temperature thin film electronics are said by the partners to have the potential to be produced cost effectively using large area manufacturing processes on plastic foils. Applications are expected to include RFID and NFC tags and sensors for smart food packaging, flexible displays, sensor arrays and OLED lamps.
Author
Graham Pitcher
Source: www.newelectronics.co.uk