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Ultrathin AlInN barrier heterostructure is the best solution for devices designed for high frequency applications.
The barrier thickness is a crucial parameter of the HEMT design. Indeed, thin barriers are required for small-signal high frequency operation to suppress short channel effects.
One of the most important advantages when using thin barrier AlInN heterostructures is the possibility to demonstrate high transconductance while keeping high channel-current densities. Therefore, AlInN is perfectly adapted for current and future applications requiring advanced designs. Indeed, AlInN/GaN HEMTs allow high aspect ratios with gate lengths smaller than 100 nm, while maintaining a high sheet carrier density.
Ultimate barrier scaling possibility
Thanks to the large polarization charge AlInN allows new HEMT designs with ultrathin barriers. The pinch-off voltage can be completely engineered from positive to negative values. For example, enhancement mode of operation is possible for a barrier thickness of 2 nm. In this configuration maximum drain current up to 0.6 A/mm is still achievable, which is well above what can be obtained with conventional AlGaN/GaN heterostructures.
Thanks to specially optimized growth processes, NOVAGAN is now able to fabricate HEMT epiwafers with Ultrathin AlInN barriers, with a thickness control at the monolayer scale and perfect composition uniformity. Heterostructures can be reliably designed and fabricated with barrier layer thicknesses approaching the tunneling thickness and the enhancement-mode characteristics.
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