Low temperature thin-film electronics based on organic and metal-oxide semiconductors have the potential to be produced in a cost effective way using large-area manufacturing processes on plastic foils. Thin-film electronics, therfore, provide an alternative solution for silicon chips in simple IC applications, such as RFID and NFC tags and sensors for smart food packaging, and in large-area electronic applications, such as flexible displays, sensor arrays and OLED lamps. Holst Centre aims to develop a robust, foil-compatible, high performance technology platform for these applications.
The MPU consists of two separate 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 a charge carrier mobility of 2cm2/Vs, while p-type transistors are small molecule organic TFTs with a mobility of up to 1cm2/Vs. The complementary logic allows for a complete standard cell library, including additional buffering in the core and the implementation of a mirror adder in the critical path. The P2ROM, configured by means of inkjet printing using a conductive silver ink, is a one-time programmable ROM memory. Divided into a hybrid complementary part and a unipolar n-TFT part, the chip is capable of operating at frequencies up to 650Hz, at an operational voltage of Vdd=10V.