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NYCU, TSMC researchers unveil innovative approach to modulate threshold voltage in ultra-thin semiconductors

Bryan Chuang, Taipei; Willis Ke, DIGITIMES Asia 0

Credit: NYCU

On October 11, Taiwan's National Yang Ming Chiao Tung University (NYCU) announced a groundbreaking research achievement in collaboration with TSMC, which has been published in the prestigious journal "Nature Communications." The achievement revolves around overcoming complex technical challenges related to threshold voltage modulation in ultra-thin layer semiconductors.

In a significant stride toward advancing semiconductor technology, NYCU has been strengthening its research collaboration with TSMC, resulting in a series of noteworthy achievements published in renowned international journals. The collaboration, bolstered by the appointment of former TSMC technology and R&D executives Chengming Hu and Jack Sun as instructors, has flourished over the years.

Their latest study, conducted by a research team led by professor Lien Der-Hsien at NYCU's Institute of Electronics in cooperation with TSMC, focuses on the introduction of a photo-thermal combination approach, which incorporates ultraviolet irradiation and oxygen annealing techniques. This innovative technique is heralding a new era in IC technology development as the semiconductor industry continually grapples with the challenges of miniaturization, according to a NYCU press release.

As the race to miniaturize semiconductor components continues, research on two-dimensional and quasi-two-dimensional thickness semiconductors is gaining momentum. However, adjusting the threshold voltage in ultra-thin transistors has been a persistent challenge due to the diminishing material dimensions, which are approaching or becoming even smaller than the size of dopant atoms. This presents difficulties in electron transport and control, rendering effective regulation of the threshold voltage a formidable problem.

In response, the research team introduced a novel photo-thermal combination method that incorporates ultraviolet radiation and oxygen annealing. This method successfully achieved a wide and large-area modulation of the threshold voltage in ultra-thin indium oxide (In2O3) transistors. Remarkably, this approach allows for both positive and negative threshold voltage adjustments, and is entirely reversible.

The breakthrough extends beyond theoretical significance. By controlling the threshold voltage, the research team has achieved practical outcomes, including a depletion-load inverter and multi-step logic elements. These results demonstrate the potential applications in low-power circuit design and non-von Neumann computing.

Furthermore, the practicality of the method has been underscored by achieving wafer-scale threshold voltage modulation through an automated laser system in collaboration with K-Jet Laser Tek. This marks a significant step forward in the field of semiconductor technology and strengthens NYCU's collaboration with TSMC, providing a promising outlook for future innovations in the semiconductor industry.