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So Ra Jeon,Sang Ho Lee,Jin Park,Ga Eon Kang,Jun Hyeok Heo,Min-Seok Kim,Seung Ji Bae,Jeong Woo Hong,In Man Kang 대한전자공학회 2023 Journal of semiconductor technology and science Vol.23 No.6
This study presents a comparative analysis of the vertical cylinder and fin-type junctionless field- effect transistors (JLFETs) based on GaN-on-GaN substrates using three-dimensional technical computer-aided design (3D TCAD) simulations. The on-current (Ion) values of the vertical cylinder and fin-type JLFETs are 6.45 and 5.63 kA/cm2, respectively. The corresponding off-current (Ioff) of the devices is calculated as 2.51 × 10−10¬ and 9.72 × 10−2¬ A/cm2, respectively. Furthermore, their corresponding Ion/Ioff ratios are 2.57 × 1013 and 5.79 × 104, respectively. Additionally, the Ioff ratio of the devices is 2.58 × 109, and the subthreshold swing (SS) is calculated as 101 and 346 mV/dec, respectively. The static resistance (Ron) and breakdown voltage (BV) represent the figure of merits of the power transistor. Herein, Ron of the vertical cylinder-type device is 0.11 µΩ•cm2, which is lower than 0.62 µΩ•cm2 of the vertical fin-type device, whereas their corresponding BVs are calculated as 2,400 and 2,037 V, respectively. These results show that the BV of the vertical cylinder-type device is ~17.8% higher than that of the vertical fin-type device. Therefore, the vertical cylinder-type GaN JLFET has a higher performance than the vertical fin-type GaN JLFET. Herein, we provide guidance in the designing of high-performance vertical GaN power transistors.
신희연,S. K. Kwon,Y. I. Chang,J. H. Lee,K. H. Park,K. S. Jeon,Y. H. Choi,M. S. Noh 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.56 No.3
An increase in the concentration of In (indium) platelets with a high In composition in In-GaN/GaN multiple quantum wells (MQWs) can deteriorate the properties of GaN-based light emitting diodes (LEDs) and laser diodes (LDs) considerably. This paper reports a microstructural characterization of In platelets with In-rich segregations in InGaN/GaN MQWs. GaN layers and InGaN/GaN MQWs were grown by using metal-organic chemical vapor deposition (MOVCD). The microstructural properties of the In platelets were examined by using transmission electron microscopy. The crystal structure and the elemental compositions of the In platelets were analyzed by both a fast Fourier transform analysis simulated from a high-resolution TEM image and electron energy loss spectroscopy. A large number of defects, such as dislocations, stacking faults and precipitates, were observed in the InGaN/GaN MQWs. In particular, many In platelets, >30 nm in size, were formed with a high In composition (≈50%) because the In composition within the InGaN well was absorbed into the In platelets. The In platelets were the result of phase separation of the InGaN/GaN MQWs and were composed of a zinc-blende structure, which is in contrast to the wurtzite structure of the normal InGaN well.
방사선빔 조사를 이용한 질화갈륨 기반 트랜지스터의 내방사선 특성 연구
금동민(Dongmin Keum),김형탁(Hyungtak Kim) 대한전기학회 2017 전기학회논문지 Vol.66 No.9
In this work, we investigated radiation hardness of GaN-based transistors which are strong candidates for next-generation power electronics. Field effect transistors with three types of gate structures including metal Schottky gate, recessed gate, and p-AlGaN layer gate were fabricated on AlGaN/GaN heterostructure on Si substrate. The devices were irradiated with energetic protons and alpha-particles. The irradiated transistors exhibited the reduction of on-current and the shift of threshold voltage which were attributed to displacement damage by incident energetic particles at high fluence. However, FET operation was still maintained and leakage characteristics were not degraded, suggesting that GaN-based FETs possess high potential for radiation-hardened electronics.
Design and Research of GaN-Based Motor Drive System with LC Output Filter
Zekai Lyu,Ming Yang,Donglin Xu,Shuyu Shang,Dianguo Xu 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5
This paper presents a gallium nitride (GaN) – based servo motor drive system. Compared to actual inverters based on insulated gate bipolar transistors (IGBTs), the proposed design extends the pulse width modulation (PWM) frequency to 100 kHz. This allows motor filters with small component sizes. Based on this, an LC filter is added to the motor drive system, and an undamped resonance suppression algorithm is proposed to suppress the resonance introduced by the filter. By adding a proper time delay, system can be stable without any additional sensors or power losses. As a result, ideal sinusoidal line-line voltage at the motor terminals, high motor efficiency and low switching noise are achieved.
Sung Yoon Kim,Jae Hwa Seo,Young Jun Yoon,Jin Su Kim,Seongjae Cho,Jung-Hee Lee,In Man Kang 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.3
Gallium nitride (GaN) is a promising material for next-generation high-power applications due to its wide bandgap, high breakdown field, high electron mobility, and good thermal conductivity. From a structure point of view, the vertical device is more suitable to high-power applications than planar devices because of its area effectiveness. However, it is challenging to obtain a completely upright vertical structure due to inevitable sidewall slope in anisotropic etching of GaN. In this letter, we design and analyze the enhancement-mode n-channel vertical GaN MOSFET with variation of sidewall gate angle by two-dimensional (2D) technology computer-aided design (TCAD) simulations. As the sidewall slope gets closer to right angle, the device performances are improved since a gradual slope provides a leakage current path through the bulk region.
김자연 ( Ja-yeon Kim ),조유현 ( Yu-hyun Cho ),박현선 ( Hyun-sun Park ),김두형 ( Doo-hyung Kim ),김민우 ( Min-woo Kim ),박종락 ( Jong-rak Park ),권민기 ( Min-ki Kwon ) 조선대학교 공학기술연구원 2016 공학기술논문지 Vol.9 No.2
GaN based LEDs have gradually replaced traditional light sources in various applications including backlight display units, traffic signals, automotive lighting, architectural lighting, and general lighting. However, improvements to the external quantum efficiency (EQE) are required for these various application. The EQE of LED is correlated to the internal quantum efficiency (IQE) and the light extraction efficiency (LEE). Although the IQE of GaN-based LEDs has reached more than 80% due to the rapid development of growth techniques for high-quality epi-layers, the LEE of the LEDs is still low because of the large refractive index difference between the GaN (nGaN=2.5) and air (nair=1). Herein, various polygon shaped(triangle, parallelogram, pentagon, hexagon, circle shaped) LEDs are compared with those of a traditional quadrangular LED to enhance LEE of LED. To estimate the enhancement of LEE, we simulated the various shaped LEDs with ray-trace simulation tools. In addition, to measure the total amount of photons emitted from LEDs in all directions, the various polygon LEDs were encapsulated and packaged with To-can. Their optical output power of polygonal shaped LED is significantly improved, compared to that of traditional quadrangular LED due to increase in LEE along to lateral direction.
김성윤,서재화,윤영준,김진수,이정희,조성재,강인만 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.3
Gallium nitride (GaN) is a promising material for next-generation high-power applications due to its wide bandgap, high breakdown field, high electron mobility, and good thermal conductivity. From a structure point of view, the vertical device is more suitable to high-power applications than planar devices because of its area effectiveness. However, it is challenging to obtain a completely upright vertical structure due to inevitable sidewall slope in anisotropic etching of GaN. In this letter, we design and analyze the enhancement-mode n-channel vertical GaN MOSFET with variation of sidewall gate angle by two-dimensional (2D) technology computer-aided design (TCAD) simulations. As the sidewall slope gets closer to right angle, the device performances are improved since a gradual slope provides a leakage current path through the bulk region.
Kim, Sung Yoon,Seo, Jae Hwa,Yoon, Young Jun,Kim, Jin Su,Cho, Seongjae,Lee, Jung-Hee,Kang, In Man The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.3
Gallium nitride (GaN) is a promising material for next-generation high-power applications due to its wide bandgap, high breakdown field, high electron mobility, and good thermal conductivity. From a structure point of view, the vertical device is more suitable to high-power applications than planar devices because of its area effectiveness. However, it is challenging to obtain a completely upright vertical structure due to inevitable sidewall slope in anisotropic etching of GaN. In this letter, we design and analyze the enhancement-mode n-channel vertical GaN MOSFET with variation of sidewall gate angle by two-dimensional (2D) technology computer-aided design (TCAD) simulations. As the sidewall slope gets closer to right angle, the device performances are improved since a gradual slope provides a leakage current path through the bulk region.
Novel Vertical GAA-AlGaN/GaN Dopingless MIS-HEMT: Proposal and Investigation
Ravi Ranjan,Nitesh Kashyap,Ashish Raman 한국전기전자재료학회 2021 Transactions on Electrical and Electronic Material Vol.22 No.4
This paper presents a gate all around (GAA) AlGaN/GaN HEMT (GAA-MIS-HEMT) with AlN as an interfacial passivation layer. Gate all around technique is used to improve the performance of device such as carrier concentration, electric field and current density at the interface of AlGaN & GaN. The enhanced control over the 2DEG due to gate all around structure helped in attaining superior performance. Al2O3 is used as a dielectric. The results of GAA-MIS-HEMT are compared with planar-MIS-HEMT, which shows that the GAA-MIS-HEMT provides better ON-state current, OFF-state current, transconductance, cutoff frequency (11 GHz) and ON-state to OFF-state current ratio (10 11 ), ON-resistance (0.9Ω-cm2 ) and subthreshold slope (63 mV/dec). All the layers of proposed structure are dopingless.
Geon Uk Kim,Young Jun Yoon,Jae Hwa Seo,Min Su Cho,Sang Ho Lee,Jin Park,Hee Dae An,So Ra Min,In Man Kang 대한전자공학회 2021 Journal of semiconductor technology and science Vol.21 No.6
In this paper, we designed and analyzed the electrical performances of gallium-nitride (GaN)-based vertical trench metal-oxide-semiconductor field-effect-transistors (MOSFETs) using three-dimensional technical computer-aided design (3-D TCAD) simulation. The cylindrical device is generally considered as superior device than the polygonal devices because it has better gate controllability. In the case of GaN-based vertical devices, however, the cylindrical device performs inferiorly to the hexagonal device in terms of crystal directions for the GaN sidewall plane such as m-plane (1-100), a-plane (11-20), and c-plane (0001). The simulation results provide an understanding and design guidelines for which electrical properties of trench FETs are affected by cross-section shape.