University of Delaware reports record-setting InAlN/GaN HEMTs on silicon

Assistant professor Yuping Zeng and a team of researchers in the University of Delaware’s Department of Electrical and Computer Engineering recently fabricated a 80nm gate-length gallium nitride (GaN) high-electron-mobility transistor (HEMT) on a silicon substrate using indium aluminium nitride (In0.17Al0.83N) as the barrier layer that demonstrates record performance (Peng Cui et al, ‘High-performance InAlN/GaN HEMTs on silicon substrate with high fTxLg, 2019 Appl. Phys. Express 12 104001).

Among devices of its type, the transistor is claimed to have record low gate leakage current (of 7.12x10−7A.mm−1), record high on/off current ratio (of 1.58x106) and (due to its DC performance) record high current-gain cutoff frequency (fT of 200GHz). The product fTxLg =16GHz.μm is also reckoned to be a new record for GaN HEMTs on silicon.

The researchers say that the transistor could be useful for higher-bandwidth wireless communication systems. For a given current, it can handle more voltage and would require less battery life than other devices of its type. “We want to expand the bandwidth of wireless communications, and this will give us more information for a certain limited time,” says Zeng. “It can also be used for space applications because the gallium nitride transistor we used is radiation robust, and it is also wide-bandgap material, so it can tolerate a lot of power,” he adds.

The transistors are made on a low-cost silicon substrate. “This process can also be compatible with silicon complementary metal–oxide–semiconductor (CMOS) technology,” notes Zeng.

“We are trying to continue to break our own record, both for the low-power application as well as for the high-speed application,” says Zeng. The team also plans to use the transistors to make power amplifiers that could be particularly useful for not only wireless communications but also Internet of Things (IoT) applications.

Several University of Delaware units helped Zeng’s group set the new record. The group fabricated their device in the UD Nanofabrication Facility. Postdoctoral scholar Peng Cui, the first author on the Applied Physics Express paper, has received funding through the Horn Entrepreneurshiip Postdoctoral Innovation Fellow program and the Air Force Office of Scientific Research.

Tags: GaN HEMT

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