RESEARCH

Si-based optical modulators 

IMEC,    July ‘18 - present

       Details to be updated soon ....

Systematic design guide for high-speed Si micro ring modulator  

Yonsei Univ.,    Apr ‘17 - present

       The Si micro-ring modulator is expected to play an important role in optical interconnect systems thanks to the large modulation bandwidth and small device footprints.  There are many reports for analysis and experimental demonstrations. However, a systematic device design guide for determining optimal doping concentrations, ring radius, and coupling strength between ring and bus waveguides for a target data rate is not available.  In this work, we study on realizing such a design guide.

Numerical analysis on high-power laser diode                         

Yonsei Univ.,     Apr ‘17 - present

       High-power laser diodes are highly attractive for material processing and military applications.  However, the performance of a laser diode is easily deteriorated by thermal effect due to high-power operation; e.g. thermal lens effect which induces low beam quality.  In this work, we numerically analyze the mechanism of the deterioration of laser diodes, and suggest the improved device structures.

Micro LED display                                

Seoul Semiconductor/Viosys     Apr ‘15 – Mar ‘17

       Micro LED is considered to be a key enabling technology for the next-generation display technology. Micro LED is based on inorganic materials, mainly GaN or GaAs, which is much more efficient than organic LEDs. However, it is difficult to package millions of micro LEDs for millions of sub-pixels of a display. In this project, we have demonstrated the packaging methods, micro-LED structures, and display structures.

US20170287887A1, Display apparatus and manufacturing method thereof, Oct. 5 ‘17

US20170250329A1, Display apparatus and manufacturing method thereof, Aug. 31 ‘17

US20170250164A1, Display apparatus and manufacturing method thereof, Aug. 31 ‘17

US 20170194304A1, Display apparatus, Jul. 6 ‘17

WO2017014564A1, Display device and method for manufacturing same, Jan 26 ‘17 

US20170025388A1, Display apparatus and manufacturing method thereof, Jan 26 ‘17

Strained SiGe optical modulator                      

Univ. of Tokyo                Apr ‘10 – Mar ‘15

       Silicon photonics is one of the most promising technologies for electronic-photonic integrated circuit.  The Si optical modulator is a key component to encode electrical signals into light.  However, the bottleneck of a Si optical modulator is low modulation efficiency due to weak electrooptical effects in Si. In this work, we introduced strained SiGe technology to boost the performance of a Si optical modulator, and successfully demonstrated as follows:

-       First demonstration of strain-induced enhancement of free-carrier effects in strained SiGe

-       Record-low injection-current strained SiGe Mach-Zehnder optical modulator

BTO-on-Si optical modulator                           

 IMEC     Aug ‘14 – Sept ‘14

       The objective of this work is to improve the modulation efficiency of a Si-based optical modulator, in conjunction with Barium titanate (BTO).  We numerically analyzed the device performance and optimized the device structure.

Graphene transistor

SAIT (SAMSUNG)  Jul ‘13 – Aug ‘13

       Graphene has attracted a lot of attention in recent years for the extremely outstanding physical properties.  The main aim of this project is to investigate ozone cleaning effect on graphene for removal of PMMA residue.

GaN Power MOSFET 

Univ. of Tokushima       Sept ‘09 – Mar ‘10

       GaN power transistors have the potential to reduce energy comparing to the  conventional Si-based power transistors due to high breakdown voltage and speed switching.  In this work, we demonstrated a GaN MOSFET with a silane-based SiO₂ insulator by PECVD, which enables operation of 15-V gate voltage with ignorable leakage current.