Professor Hong has worked in many research topics, from superconductivity, magnetism, semiconductor lasers, to advanced electronic devices.

In 1994, he and his colleagues at Bell Labs discovered a novel oxide of Ga2O3(Gd2O3), which gives the oxide-GaAs hetero-structure a low interfacial trap density, thus solving a problem which has puzzled researchers for the last 35 years. This has led to the first demonstration of inversion-channel GaAs/InGaAs MOSFETs, the Holy Grail in compound semiconductor electronics.

From 2003 to now, he and Professor J. Raynien Kwo, and our research group members have made landmark contributions to achieve
Very low interfacial trap densities
Very low electrical current leakage
High-temperature (900C) stability of the high k/III-V (and Ge) MOS
Surface Fermi level unpinning mechanism
Sub-nm EOT in the high k's in III-V and Ge

Among many other critical properties, essential for the technology beyond 3 nm node CMOS. Moreover, our group members have fabricated self-aligned inversion-channel InGaAs MOSFETs with world-record high drain currents and transconductances.

The present research activities in Prof. Hong's group, in collaboration with

Prof. Kwo of National Tsing Hua University.
Drs. T. W. Pi, C. H. Hsu, C. M. Cheng of National Synchrotron Radiation Research Center.
Prof. Dr. L. H. Tjeng of Max Planck Institute for Chemical Physics of Solids, Dresden, Germany.
Drs. T. Maeda, W. H. Chang of National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, Japan.

Research topics

Tailoring atomic-scale hetero-interfaces in oxides, metals, and semiconductors:

scientific understanding and device advances

In the past few decades, in addition to silicon complementary MOS (CMOS) technology or radio frequency (RF) applications, people have also called for the use of various high-mobility semiconductors. Achieving the same high-quality dielectric/semiconductor interface, such as high dielectric constant growth on Ge, has become increasingly important. Therefore, the realization of the high-quality oxide/high-mobility semiconductor interface not only meets the strong demand for high-speed and low-power device applications but also provides different methods to study the successful realization of the basic surface passivation of semiconductors

IV group semiconductor(Si, Ge)

In the past few decades, in addition to silicon complementary MOS (CMOS) technology or radio frequency (RF) applications, people have also called for the use of various high-mobility semiconductors. Achieving the same high-quality dielectric/semiconductor interface, such as high dielectric constant growth on Ge, has become increasingly important. Therefore, the realization of the high-quality oxide/high-mobility semiconductor interface not only meets the strong demand for high-speed and low-power device applications but also provides different methods to study the successful realization of the basic surface passivation of semiconductors.

Solving important Ge MOS problem for the production of next generation (~present)

low-temperature Si-capped Si1-xGex gate stacks to achieve low Dit of 2~6E11 cm^-2eV^-1 with Ge content from 0.5 to 1.0.
Thin single crystal Si-capped Ge(100), (110), and (111) Gate Stacks - Attainment of Low Interfacial Trap Density for FinFET Application and the Reliability. [very low Dit=6E10 cm-2^eV^-1 in the Si-capped Ge(110)].

III-V group semiconductor(GaAs, InGaAs)

Groundbreaking research on III-V semiconductor metal oxide semiconductor field-effect transistors, including the use of high dielectric constant oxide films on GaAs surfaces with low interface trap states and unpinned Fermi levels. The discovery and the first demonstration of the inverted channel GaAs MOSFET are the latest technologies in the field of science and technology other than Si CMOS.

III-V semiconductors with inherently high electron mobility and energy band engineering capabilities are now widely used in a variety of high-speed electronic and optoelectronic devices and are also candidates for future CMOS technology.

High-quality oxide/III-V interfaces again need to minimize interface scattering to maintain high electron mobility in III-Vs.
In our laboratory, by depositing in-situ Y2O3 on the original InGaAs surface, it demonstrated a perfect high-k/InGaAs heterostructure with low interface trap density (Dit level of 3-8E11 cm^-2eV^-1) and high thermal stability.

Hexagonal YAlO3

Perovskite materials, because of their superconducting, ferroic, and optical properties, have been studied for several decades in bulk crystals and thin films. For integration with nanoelectronics, growth of perovskites thin-film on semiconductor substrates utilizing mass production compatible tools such as ALD, enabling us to revolutionize the future technology. During the past few years, we have successfully integrated the single-crystal hexagonal yttrium aluminum perovskite (H-YAP) onto important III-V compound semiconductors GaAs and GaN. Excellent crystallinity of H-YAP was observed from both synchrotron radiation XRD and spherical aberration-corrected STEM despite the large film/substrate lattice mismatch. Recently, we have made great progress on the understanding of the mechanism of the epitaxy of H-YAP on GaAs, which will enable us to integrate various perovskites on the important semiconductors for the future opto- and nano-electronics.

Related Publication:

L. B. Young et al., J. Vac. Sci. Technol. A 35, 01B123 (2017)

C. K. Cheng et al., Microelectron. Eng. 178, 125 (2017)

L. B. Young et al., Cryst. Growth Des. 19, 2030 (2019)

Patent:

"Material having single crystal perovskite, device including the same, and manufacturing method thereof", US Patent App. 15/487,769

Research fields