TFT Fabrication Method May Improve Display Technology

An alternative to the traditional processes used to produce thin-film transistors (TFTs) could lead to improvements in LCD and OLED displays for TVs, smartphones, computers, and tablets.

Researchers grew a crystalline silicon thin film on buffered soda-lime glass below 600 °C from a gold (Au)-silicon (Si) eutectic melt with electron mobility of 188 cm²V⁻¹s⁻¹.

They characterized the film using x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), Raman spectroscopy, cross-section scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Characterization methods confirmed a thin continuous film of highly crystalline silicon grown on buffered soda-lime glass.

According to researchers, this process could replace low-temperature polysilicon (LTPS) in the fabrication of TFTs for driving pixels in large displays.

TFTs are typically produced using one of three processes: amorphous silicon (a-Si:H), low-temperature polysilicon (LTPS), or indium gallium zinc oxide (IGZO). The new research suggests that there is an opportunity to replace these processes.

The technology was invented by the late Praveen Chaudhari, materials physicist and recipient of the U.S. National Medal of Technology. Ashok Chaudhari, CEO of Solar-Tectic LLC, and Ratnakar D. Vispute of Blue Wave Semiconductors Inc., oversaw and made the samples, exactly following Chaudhari’s recipe, which is patented. The samples were tested by Binghamton University’s Center for Autonomous Solar Power (CASP).

“While the research provides a way to improve the quality of displays and lower cost, it can also improve the production of electronic devices like solar cells,” said Tara Dhakal, director of CASP.

The research was published in Materials Letters (doi:10.1016/j.matlet.2018.02.080).