The new method removes the uncertainty from oxide semiconductor coatings
(Nanowerk News) 3D integrated circuits are an important part in increasing the efficiency of electronics to meet the huge consumer demands. They are constantly being developed, but translating theoretical findings into actual devices is not easy. Now, a new design by a team of researchers from Japan could turn that theory into reality.
In a study recently published for VLSI Symposium 2023 (“A Nanosheet Oxide Semiconductor FET Using ALD InGaOx Channel and InSnOX Electrodes with Normally Off Operation, High Mobility and Reliability for 3D Integrated Devices”), researchers from the Institute of Industrial Science, University of Tokyo have reported a deposition process for oxide nanosheet semiconductors. The oxide semiconductors produced from this process have high carrier mobility and reliability in transistors.
A 3D integrated circuit consists of several layers, each of which plays a role in the overall function. Oxide semiconductors have attracted a lot of attention as materials for various circuit components because they can be processed at low temperatures, yet have high carrier mobility and low charge leakage, as well as being able to withstand high voltages.
There is also an advantage of using oxides rather than metals in processes where the electrode may be exposed to oxygen during the integration process and become oxidized.
However, developing the processes required to reliably deposit very thin layers of oxide semiconductor materials in device manufacturing is challenging and has not been fully defined to date. Recently, researchers have reported an atomic layer deposition (ALD) technique that generates layers suitable for large-scale integration.
“Using our process, we conducted a systematic study of field-effect transistors (FETs) to determine their limits and optimize their properties,” explains the study’s lead author, Kaito Hikake. FET controls the flow of current in semiconductors. “We adjusted the component ratios and adjusted the preparation conditions and our findings led to the development of multi-gate nanosheet FETs for normal operation and high reliability.”
The findings revealed that the FETs fabricated from the oxide semiconductors selected by ALD had the best performance. The multi-gate nanosheet FET is believed to be the first to combine high carrier mobility and reliability characteristics with normal operation.
“In a fast-moving field like electronics, it is important to translate a founding proof of concept into relevant industrial processes,” said Masaharu Kobayashi, senior author. “We believe that our research provides robust techniques that can be used to produce devices that meet the market’s need for high-functionality manufacturable 3D integrated circuits.”
The findings in this research have provided a solution to one of the major hurdles in the manufacture of electronic devices with semiconductors. Hopefully this will bring more high-functionality electronic designs to actual products.
