A team of researchers from the Institute of Industrial Science at The University of Tokyo has made significant progress in the development of 3D integrated circuits. Their recent study, published in the VLSI Symposium 2023, unveils a novel deposition process for nanosheet oxide semiconductors. These semiconductors demonstrate high carrier mobility and reliability in transistors, making them a promising material for various circuit components.
Unlike metals, oxide semiconductors can withstand high voltages and can be processed at low temperatures. They also have the advantage of resisting oxidation when exposed to oxygen during the integration process, which is a common concern with electrode materials.
However, depositing thin layers of oxide semiconductors reliably in device manufacturing has been a challenge. The researchers have now introduced an atomic layer deposition (ALD) technique that can produce suitable layers for large-scale integration.
Lead author Kaito Hikake explains, “Through our process, we conducted a comprehensive study of field effect transistors (FETs) to identify their limitations and optimize their properties. By adjusting the preparation conditions and component ratios, we successfully developed a multi-gate nanosheet FET capable of normally-off operation and exhibiting high reliability.”
The study demonstrates that FETs created using the ALD technique with the selected oxide semiconductor deliver the best performance. This multi-gate nanosheet FET represents a breakthrough as it combines high carrier mobility, reliability, and normally-off operation.
Senior author Masaharu Kobayashi emphasizes the importance of translating proof of concept findings into practical industrial processes, particularly in rapidly evolving fields like electronics. He believes that their study presents a robust technique for manufacturing 3D integrated circuits with high functionality, meeting the market’s demand for such devices.
The findings of this study have the potential to overcome a major obstacle in semiconductor device manufacturing. With the successful implementation of this technique, it is expected that more electronics with enhanced functionality will be developed and brought to market in the future.
Source: University of Tokyo