Scientists in the US have found a way to increase the performance of transistors using a paradoxical physical phenomenon – negative capacitance. This discovery could help overcome the limitations set by the laws of physics and create more powerful and efficient chips.
Negative Capacitance Is the Key to New Possibilities
The phenomenon of negative capacitance manifests itself in ferroelectrics, which can retain an internal electromagnetic field even after the external influence is removed. Scientists from the Lawrence Berkeley National Laboratory and the University of California have studied transistor structures with a ferroelectric layer.
Breaking the Schottky Limit
The Schottky limit defines a trade-off between the thickness of the insulator that prevents leakage current and the magnitude of the on-state current, as well as the speed of switching between these modes. Negative capacitance allows to overcome this trade-off and provide an increase in the performance of GaN transistors.
Experiment and results
The scientists conducted an experiment on a prototype transistor using a ferroelectric compound of hafnium oxide and zirconium oxide (HfO₂-ZrO₂). The results showed that increasing the thickness of the dielectric does not reduce the switching speed.
Practical application
- Negative capacitance effectively enhances gate drive by promoting charge accumulation in the transistor's two-dimensional electron cloud and increasing the on-current.
- The thickness of the HZO dielectric suppresses the leakage current when the device is turned off, which saves energy.
Prospects and future research
The scientists are looking for interested partners to reproduce the experiment in conditions of mass production of transistors. It is necessary to reduce the size of the transistor and verify the operability of such structures on a smaller scale.
This discovery could have significant implications for the development of microelectronics and the creation of more powerful and efficient chips.
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