editor's blog
Subscribe Now

Inorganic n-Type Thin-Film Transistors

We’ve seen before that organic approaches to transistors have focused on p-type transistors. While n-type materials have become more available, organic CMOS still isn’t widespread.

In an ISSCC paper, imec made reference to an inorganic thin-film transistor (TFT) that makes use of metal oxide (I’m tempted to call these MOxFETs). We’ll have more on that story in another posting; before getting into that, however, I wanted to learn more about exactly what these MOxFETs are.

It turns out that metal-oxide TFTs have been worked on for some time, but with a couple processing variants that limited their use. Vacuum sputtering, which yields the best mobility (> 10 cm2/Vs) costs money and limits the size of the circuit; solution-based materials are more promising because they can be deposited under “ambient” conditions over a larger substrate.

But there has still been one issue: these devices had to be annealed at temperatures of 350 °C and higher, limiting the materials that could be used in the processing. So imec’s contribution was an indium-based solution that could be annealed at 250 °C. This let them deposit this stuff on flexible substrates. While not performing as well as sputtered films, they still achieved mobility over 2 cm2/Vs.

Just as n-type organic devices have left something to be desired, so metal-oxide p-type devices aren’t so great – better materials and a wider processing window are needed. But it’s possible to use the inorganic n-type with the organic p-type to build complementary circuits.

The process starts with the gate contacts and Al2O3 high-K gate at the bottom of the stack, and then lays down the metal-oxide layer, with metal over that for the source/drain contacts. The pentacene organic film is then laid down, contacting that same metal layer from above for its source and drain.

More details can be found in their paper, “Low-temperature and scalable complementary thin-film technology based on solution-processed metal oxide n-TFTs and pentacene p-TFTs” published in Organic Electronics on 8/26 of last year.

Leave a Reply

featured blogs
Jan 17, 2022
Today's interview features Dajana Danilovic, an application engineer based near Munich, Germany. In this video, Dajana shares about her pathway to becoming an engineer, as well as the importance of... [[ Click on the title to access the full blog on the Cadence Community sit...
Jan 13, 2022
See what's behind the boom in AI applications and explore the advanced AI chip design tools and strategies enabling AI SoCs for HPC, healthcare, and more. The post The Ins and Outs of AI Chip Design appeared first on From Silicon To Software....
Jan 12, 2022
In addition to sporting a powerful processor and supporting Bluetooth wireless communications, Seeed's XIAO BLE Sense also boasts a microphone and a 6DOF IMU....

featured video

Synopsys & Samtec: Successful 112G PAM-4 System Interoperability

Sponsored by Synopsys

This Supercomputing Conference demo shows a seamless interoperability between Synopsys' DesignWare 112G Ethernet PHY IP and Samtec's NovaRay IO and cable assembly. The demo shows excellent performance, BER at 1e-08 and total insertion loss of 37dB. Synopsys and Samtec are enabling the industry with a complete 112G PAM-4 system, which is essential for high-performance computing.

Click here for more information about DesignWare Ethernet IP Solutions

featured paper

Using the MAX66242 Mobile Application, the Basics

Sponsored by Analog Devices

This application note describes the basics of the near-field communication (NFC)/radio frequency identification (RFID) MAX66242EVKIT board and an application utilizing the NFC capabilities of iOS and Android® based mobile devices to exercise board functionality. It then demonstrates how the application enables the user with the ability to use the memory and secure features of the MAX66242. It also shows how to use the MAX66242 with an onboard I2C temperature sensor which demonstrates the energy harvesting feature of the device.

Click to read more

featured chalk talk

Solutions for Heterogeneous Multicore

Sponsored by Siemens Digital Industries Software

Multicore processing is more popular than ever before but how do we take advantage of this new kind of processing? In this episode of Chalk Talk, Jeff Hancock from Siemens and Amelia Dalton investigate the challenges inherent in multicore processing, the benefits of hypervisors and multicore frameworks, and what you need to consider when choosing your next multicore processing solution.

Click here for more information about Multicore Enablement: Enabling today’s most advanced MPSoC systems