Researchers realize gallium nitride-based complementary logic integrated circuits

Most integrated circuits (ICs) and physics components developed to day are based connected silicon metal-oxide-semiconductor (CMOS) technology. As silicon (Si) is known to person a constrictive bandgap, however, successful caller years engineers person been trying to make ICs utilizing different materials with a wider bandgap, specified arsenic gallium nitrite (GaN).

ICs made of GaN could person notable advantages implicit accepted ICs based connected silicon, peculiarly for the improvement of powerfulness electronics, radiofrequency powerfulness amplifiers and devices designed to run successful harsh environments. However, truthful acold processing GaN CMOS logic circuits has proved to beryllium highly challenging, owed to the intrinsically debased mobility of holes successful the worldly and the deficiency of a suitable strategy for integrating n-channel and p-channel field-effect transistors (n-FETs and p-FETs) connected a azygous substrate.

Researchers astatine the Hong Kong University of Science and Technology (HKUST) person precocious realized a bid of GaN-based complementary logic ICs. Their paper, published successful Nature Electronics, could person important implications for the improvement of caller types of electronics.

"Our enactment connected GaN complementary logic integrated circuits (ICs) was carried retired connected a GaN-on-Si powerfulness HEMT (high-electron-mobility transistor) level that presently dominates the mainstream commercialized GaN powerfulness electronics instrumentality technology," Prof. Kevin J. Chen, who led this study, told Tech Xplore. "This is simply a planar exertion that is peculiarly suitable for the high-density integration of multi-functional blocks."

To beryllium businesslike and complete, a powerfulness conversion strategy requires some halfway powerfulness switching devices, specified arsenic powerfulness transistors and rectifiers, and peripheral circuits that alteration their driving, sensing, protective and power functionalities. Therefore, to unlock the afloat imaginable of GaN powerfulness HEMTs, enabling their high-frequency cognition and the realization of smaller, much compact powerfulness systems, it would beryllium preferable for powerfulness switching devices and peripheral circuits to beryllium seamlessly integrated connected a azygous chip.

"Current GaN HEMTs are each n-FETs with electrons arsenic the carriers, frankincense each the peripheral circuits are besides based connected n-FETs," Dr. Zheyang Zheng, 1 of the researchers who carried retired the study, explained. "However, logic gates (which are a large constituent successful the peripheral circuits) solely based connected n-FETs, are overmuch little energy-efficient than the well-known CMOS (complementary MOS) logic architecture that features complementary n-FETs and p-FETs."

The main nonsubjective of the caller survey was to make GaN complementary oregon CMOS-like logic ICs that are compatible with existing GaN powerfulness HEMT platforms. Due to their advantages and wide bandgap, these ICs could payment a wide scope of technological applications, peculiarly those that are constricted by the narrower bandgap of Si-based ICs.

"We show a suitable strategy to monolithically integrate GaN n-FETs and p-FETs and manifests the feasibility of constructing GaN-based complementary logic integrated circuits," Zheng said. "Logic gates based connected complementary n-FETs and p-FETs (i.e., the complementary logic gates) are the astir vigor businesslike architectures for implementing integer logic circuits, arsenic the usage of complementary n-FETs and p-FETs results successful substantially suppressed static powerfulness dissipation astatine some logic states (i.e., logic "1" and "0"), rail-to-rail input and output capability, well-placed logic modulation threshold, and ample sound margins."

Using their fabrication strategy, Zheng and his colleagues demonstrated a afloat household of simple logic gates, including NOT (inverter), NAND, NOR and transmission gates. In addition, arsenic analyzable ICs necessitate logic circuits featuring aggregate signifier logic gates, the squad besides demonstrated multi-stage integer ICs, specified arsenic a latch compartment and ringing oscillators, that tin run some astatine country somesthesia and astatine higher temperatures.

"Our survey unambiguously manifests the feasibility of implementing GaN-based complementary logic circuits by demonstrating some a implicit acceptable of simple logic gates and 2 multistage circuits," Chen said. "Our findings connote that each GaN-based complementary logic circuits are technically wrong reach. Firstly, each gathering blocks are available. Secondly, they tin beryllium integrated unneurotic for much analyzable entities."

To make their GaN-based complementary circuits, the researchers utilized a commercialized p-GaN gross powerfulness HEMT platform. The usage of this commercialized level enables the integration of the complementary circuits they developed with existing powerfulness devices. As portion of their study, the squad besides demonstrated the feasibility of this integration.

"As a first-generation objection with comparatively ample captious instrumentality dimension, our circuits tin already enactment astatine sub-megahertz frequencies," Zheng said. "It could beryllium foreseen that mean instrumentality downscaling and further betterment of the fabrication process would propulsion the operating frequence to tens of megahertz, which would comfortably fulfill the requirements of presently utilized GaN-based powerfulness systems."

The ICs that this squad of researchers presented successful their caller insubstantial are based connected a GaN p-channel FET exertion they worked connected for the past 2 years. Using a caller oxygen plasma attraction technique, Zheng and his colleagues were capable to simultaneously attain p-FET characteristics desirable for CMOS technology, including an enhancement-mode operation, debased gross leakage, decent existent density, and a precocious ON/OFF existent ratio.

In the future, the ICs they created could assistance the improvement of a wide scope of technological devices, including tools for powerfulness conversion, lipid well-logging, pitchy motor power and abstraction exploration. Meanwhile, the researchers program to analyse ways successful which they could heighten their ICs further.

"We are going to enactment connected down-scaling the devices, particularly the p-channel transistors, for higher operating velocity and little powerfulness consumption," Zheng added. "As these circuits are made connected a commercialized GaN-on-Si level for manufacturing GaN powerfulness HEMTs, we would question collaboration with the manufacture to deploy GaN complementary logic circuits successful the peripheral circuits and integrate with the powerfulness HEMT for constructing much energy-efficient power conversion systems."

---

---

© 2021 Science X Network