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1 With a number of excellent features, GaN HEMTs have been expected to significantly upgrade the performance of existing power converters. GaN-based power devices having excellent switching and temperature capabilities, are able to achieve a system with muc + 1489 word(s) 1489 2019-11-25 08:44:19 |
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Ma, C. Gallium Nitride High-Electron-Mobility Transistor. Encyclopedia. Available online: https://encyclopedia.pub/entry/158 (accessed on 12 October 2024).
Ma C. Gallium Nitride High-Electron-Mobility Transistor. Encyclopedia. Available at: https://encyclopedia.pub/entry/158. Accessed October 12, 2024.
Ma, Chao-Tsung. "Gallium Nitride High-Electron-Mobility Transistor" Encyclopedia, https://encyclopedia.pub/entry/158 (accessed October 12, 2024).
Ma, C. (2019, November 29). Gallium Nitride High-Electron-Mobility Transistor. In Encyclopedia. https://encyclopedia.pub/entry/158
Ma, Chao-Tsung. "Gallium Nitride High-Electron-Mobility Transistor." Encyclopedia. Web. 29 November, 2019.
Gallium Nitride High-Electron-Mobility Transistor
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In recent years, GaN-based devices have been widely used in a variety of application fields. GaN-based high-electron-mobility transistors (HEMTs) are superior to conventional silicon (Si) based devices in terms of switching frequency, power rating, thermal capability and efficiency, which are crucial factors to enhance the performances of advanced power converters. This paper addresses some fundamental issues concerning intrinsic features of GaN material and key technology in practical application of GaN-based power switching devices.

gallium nitride (GaN) silicon carbide (SiC) Power converter

 1. Introduction

In recent years, Gallium nitride (GaN) has become a popular semiconductor material widely used in the fabrication of advanced electronic and power switching devices. Compared with conventional silicon (Si) material, GaN has a number of intrinsic merits, e.g. wide bandgap, high critical breakdown electric field, high thermal conductivity, and high electronic saturation velocity. GaN-based power switching devices benefit from the two-dimensional electron gas (2DEG) can offer small on-resistances, high current capabilities, and power densities[1]. In the past five years, commonly used GaN-based power switching devices include enhancement mode (E-mode) GaN high electron mobility transistors (HEMTs), cascode GaN HEMTs, and lateral GaN MOSFETs. Unlike using depletion-mode (D-mode) GaN HEMTs, which are normally on, the potential danger of short circuit can be greatly decreased using the normally off devices. It is worth mentioning that a cascode GaN HEMT constructed by a high-voltage D-mode GaN HEMT and a high-speed, low-voltage, and normally-off Si MOSFET allows the on-state losses and switching losses to be significantly reduced while retaining the desired normally-off characteristic. Compared with GaN HEMTs, lateral GaN MOSFETs are less susceptible to hot electron injection and current collapse, and have higher cut-off voltages, making them an even more promising choice for high-voltage applications. However, lower channel mobility due to the absence of 2DEG is an obvious drawback [1][2]. Driving design is a challenging task in using GaN HEMTs, single channel techniques are normally used in high-switching-frequency design cases because this method offers higher reliability than that of simultaneously driving both high-side and low-side GaN HEMTs using a dual-channel driving technique. The driving of a cascode GaN HEMT is relatively easy since it is similar to driving a Si-MOSFET. On the other hand, driving an E-mode GaN HEMT has to consider some complex factors because of E-mode GaN HEMT’s high voltage and current slew rates, low threshold voltage, and low allowable gate voltages. The high switching speed also makes parasitic issues become severe, and thus the layout requires special considerations. The constraints related to low driving voltage can be handled with a separate turn-on and turn-off driving path design. To avoid voltage overshoot due to high slew rate, voltage clamp is commonly used. To mitigate parasitic induced issues, it is recommended to use a Kelvin connection and an optimized circuit board layout so that the overlapping between power loop and driving loop is minimized. To ensure successful turn-off operations, negative driving voltage can be used, but this may increase reverse conduction loss and requires extra power supply units. Voltage clamp is a good alternative [3][4][5].

2. Key Application Issues

Semiconductor devices are very commonly used in a variety of power conversion systems. Enhancing the power conversion efficiency means improving the overall energy utilization rate. Because Si-based power switches have low linearity in output capacitance, high output charge, high reverse recovery charge, and high gate charge, they are not expected to be used in designing advanced power converters meeting the required high system efficiencies and power densities [6]. WBG materials such as GaN and SiC offer substantial advantages over Si for power semiconductor applications, as shown in Figure 1.

Electronics 08 01401 g006

Figure 1. Comparison of Si, gallium nitride (GaN), and silicon carbide (SiC) for power semiconductor applications.

As can be seen in Figure 1, SiC offers superior thermal conductivity, while GaN has the highest bandgap and electron mobility. Over the past few years, WBG material-based switching devices were intensively researched to achieve their full potential. These devices, with proper design, not only benefit existing power conversion systems but also provide new possibilities in improving some of the existing power electronic systems. SiC-based devices outperform Si-based devices tremendously in high-power (over 600 V) applications and are currently considered the most suitable devices for efficient power conversion at the abovementioned voltage level. However, quality material for SiC-based devices is quite limited and, thus, increasingly costly. As a result, GaN-based devices are considered potential alternatives to SiC-based devices in applications of low- to medium-level voltage. Commercially available GaN-based power switching devices offer an operating voltage ranging from 100 V to 1200 V, high switching frequency and operation temperature capabilities, and reduced switching losses. However, the very low threshold voltage (VGS_th) in normally off GaN devices is a technical problem in practical applications. Moreover, SiC-based devices still dominate applications with voltage levels over 1000 V [7][8].

GaN HEMTs are naturally on because of the two-dimensional electron gas (2DEG) that allows high current. Normally on GaN HEMTs, also known as depletion mode (D-mode) GaN HEMTs, can be turned off by applying negative VGS_th. Technical reports verify that various methods can be used to deplete the 2DEG path of a D-mode GaN HEMT and to realize the desired normally off switching characteristics. Commercially available normally off GaN HEMTs are divided into two types: enhancement mode (E-mode) and cascode configuration. E-mode GaN HEMT can be turned on by applying positive VGS_th. Generally, the sum of external resistance and driver output resistance should be designed as much larger than the internal resistance of an E-mode GaN HEMT in order to reduce the influence of internal resistance on the switching speed and reduce voltage overshoot. In practice, cooling is also crucial for further reducing conduction losses. In the aspect of driving E-mode GaN HEMT, the limit of peak driving voltage, the damping of driving charges, and the input/output propagation delay should be taken into consideration. Also, it is recommended to incorporate a Miller clamp, negative voltage source, and separate paths for turn-on and turn-off processes [9]. Cascode GaN HEMT combines a D-mode GaN HEMT and a normally off high-speed Si metal–oxide–semiconductor field-effect transistor (MOSFET) to realize a normally off characteristic, and it can be turned on by applying positive VGS_th on the Si MOSFET. For switching frequency over 100 kHz, it is recommended to use separate turn-on and turn-off paths, Kelvin source connection, ferrite beads, and minimized turn-off resistance and inductance of the driving loop [10]. Various driving circuits for GaN HEMTs were explored in References[9][10][11][12][13][14][15][16][17][18]. Discussion and designs for GaN HEMT driving circuits were provided in References[19][20][21]. The designs of special undervoltage lockout circuit and low-inductance driving circuits were discussed in References  and [23], respectively.

In the aspect of device specifications, current voltage ratings of commercial GaN HEMTs are up to 650 V, as shown in Table 1, where Vds represents drain-source voltage, Id represents drain-source current, VTH represents threshold voltage, Vgs represents gate-source voltage, Rds(on) represents on resistance, and Ciss represents input capacitance. Transphorm mainly produces 650-V cascode GaN HEMTs and evaluation boards for various applications based on their own GaN HEMTs. GaN System mainly produces 650-V and 100-V E-mode GaN HEMTs. Various GaN half-bridge evaluation boards are also commercialized for potential researchers. Texas Instruments (TI) and Silicon Labs produce both single-channel and dual-channel gate drivers suitable for GaN HEMTs, as shown in Tables 2 and 3, respectively. TI also produces GaN switching modules that integrate GaN HEMTs with designed drivers as shown in Table 4.

Table 1. Commercial gallium nitride (GaN) high-electron-mobility transistors (HEMTs) by Transphorm and GaN Systems.

Manufacturer

Device

Vds (V)

Id (A)

VTH (V)

Vgs (V)

Rds(on) (mΩ)

Ciss (pF)

Transphorm

TPH3206PSB

650

16

2.1

±18

150

720

Transphorm

TPH3208PS

650

20

2.1

±18

130

760

Transphorm

TPH3212PS

650

28

2.6

±18

72

1130

Transphorm

TP65H050WS

650

34

4

±20

60

1000

Transphorm

TPH3205WSBQA

650

35.2

2.1

±18

62

2200

Transphorm

TPH3205WSB

650

36

2.6

±18

63

2200

Transphorm

TP65H035WS

650

46.5

4

±20

35

1500

Transphorm

TPH3207WS

650

50

2.65

±18

41

2197

Transphorm

TP90H180PS

900

15

2.1

±18

205

780

GaN Systems

GS66502B

650

7.5

1.3

−10 to +7

200

65

GaN Systems

GS66504B

650

15

1.3

−10 to +7

100

130

GaN Systems

GS66506T

650

22

1.3

−10 to +7

67

195

GaN Systems

GS66508B

650

30

1.3

−10 to +7

50

260

GaN Systems

GS66508P

650

30

1.7

−10 to +7

50

260

GaN Systems

GS66508T

650

30

1.7

−10 to +7

50

260

GaN Systems

GS66516B

650

60

1.3

−10 to +7

25

520

GaN Systems

GS66516T

650

60

1.3

−10 to +7

25

520

Table 2. Commercial GaN HEMT drivers by Texas Instruments (TI).

Driver

Number of Channels

Peak Output Current (A)

Supply Voltage (V)

Rise Time (ns)

Fall Time (ns)

Propagation Delay (ns)

LMG1020

1

7

5

4

1.9

2.5

LMG1205

2

5

4.5–5.5

7

3.5

35

LMG1210

2

1.5

5

5.6

3.3

10

LM5113-Q1

2

5

4.5–5.5

7

3.5

30

UCC27611

1

6

4–18

9

4

14

Table 3. Commercial GaN HEMT drivers by Silicon Lab.

Driver

Number of Channels

Peak Output Current (A)

Input Supply Voltage (V)

Output Supply Voltage (V)

Rise Time (ns)

Fall Time (ns)

Propagation Delay (ns)

Si823x series

2

0.5 or 4

4.5–5.5 or 2.7–5.5

6.5–24

20 or 12

20 or 12

60

Si826x series

1

0.6 or 4

X

6.5–30

5.5

8.5

60

Si827x series

2

4

2.5–5.5

4.2–30

10.5

13.3

60

Si8220/1

1

0.5/2.5

X

6.5–24

30 or 20

30 or 20

60/40

Si8239x series

2

4

2.5–5.5

6.5–24

12

12

30

Si8285/6

1

4

2.8–5.5

9.5–30

5.5

8.5

50

Table 4. Commercial GaN switching modules by TI.

Module

Number of Channels

Voltage and Current Ratings (V, A)

Supply Voltage (V)

Rise Time (ns)

Fall Time (ns)

Propagation Delay (ns)

LMG3410

1

600, 12

5

4.2

15

20

LMG3410R050

1

600, 12

12

15

1.2

20

LMG3410R070

&

LMG3411R070

1

600, 40

12

15

4.2

20

LMG5200

2

80, 10

5

X

X

29.5

References

  1. Xiaofeng Ding; Yang Zhou; Jiawei Cheng; A Review of Gallium Nitride Power Device and Its Applications in Motor Drive. China Electrotechnical Society Transactions on Electrical Machines and Systems 2019, 3, 54-64, 10.30941/cestems.2019.00008.
  2. Ahmad Hassan; Yvon Savaria; Mohamad Sawan; GaN Integration Technology, an Ideal Candidate for High-Temperature Applications: A Review. IEEE Access 2018, 6, 78790-78802, 10.1109/access.2018.2885285.
  3. Nikita Hari; Teng Long; Edward Shelton; Investigation of gate drive strategies for high voltage GaN HEMTs. Energy Procedia 2017, 117, 1152-1159, 10.1016/j.egypro.2017.05.240.
  4. "How to Drive GaN Enhancement Mode Power Switching Transistors," GaN Systems, Oct. 2014.
  5. "GN001 Application Guide: Design with GaN Enhancement mode HEMT," GaN Systems, Feb. 2018.
  6. Edward A. Jones; Fei Fred Wang; Daniel Costinett; Review of Commercial GaN Power Devices and GaN-Based Converter Design Challenges. IEEE Journal of Emerging and Selected Topics in Power Electronics 2016, 4, 707-719, 10.1109/jestpe.2016.2582685.
  7. Spaziani, L.; Lu, L. Silicon, GaN and SiC: There's room for all: An application space overview of device considerations. In Proceedings of 2018 IEEE 30th International Symposium on Power Semiconductor Devices and ICs (ISPSD), Chicago, IL, USA, 13-17 May 2018.
  8. Viswan, V. A review of silicon carbide and gallium nitride power semiconductor devices. IJRESM 2018, 1, 224-225.
  9. Hassan, H.A. A GaN Based Dual Active Bridge Converter to Interface Energy Storage Systems with Photovoltaic Panels. M. S., Miami University, Oxford, Ohio, USA, 2017.
  10. Pajnić, M.; Pejović, P.; Despotović, Ž.; Lazić, M.; Skender M. Characterization and gate drive design of high voltage cascode GaN HEMT. In Proceedings of 2017 International Symposium on Power Electronics (Ee), Novi Sad, Serbia, 19-21 October 2017.
  11. Shojaie, M.; Elsayad, N.; Tabarestani, S.; Mohammed, O.A. A Bidirectional Buck-boost Converter Using 1.3kV Series-Stacked GaN E-HEMT Modules for Electric Vehicle Charging Application. In Proceedings of 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA), Atlanta, GA, USA, 31 October-2 November 2018.
  12. Shu, W.; Li, S.; Lu, S. Bi-Directional and Single Phase AC-DC Converter with Integrated LCL Filter and GaN E-HEMTs. In Proceedings of 2018 IEEE Transportation Electrification Conference and Expo (ITEC), Long Beach, CA, USA, 13-15 June 2018.
  13. Acuña, J.; Seidel, A.; Kallfass, I. Design and implementation of a Gallium-Nitride-based power module for light electro-mobility applications. In Proceedings of 2017 IEEE Southern Power Electronics Conference (SPEC), Puerto Varas, Chile, 4-7 December 2017.
  14. Gui, Y. Gate Driver for Phase Leg of Parallel Enhancement-Mode Gallium-Nitride (GaN) Transistors. M. S., Virginia Polytechnic Institute and State University, Blacksburg, VA, USA, 15 May 2018.
  15. Ng, W.T.; Yu, J.; Wang, M.; Li, R.; Zhang, W. Design Trends in Smart Gate Driver ICs for Power GaN HEMTs. In Proceedings of 2018 14th IEEE International Conference on Solid-State and Integrated Circuit Technology (ICSICT), Qingdao, China, 31 October-3 November 2018.
  16. Li, B.; Zhang, R.; Zhao, N.; Wang, G.; Huo, J.; Zhu, L.; Xu, D. GaN HEMT Driving Scheme of Totem-Pole Bridgeless PFC Converter. In Proceedings of 2018 IEEE International Power Electronics and Application Conference and Exposition (PEAC), Shenzhen, China, 4-7 November 2018.
  17. Wu, H.; Fayyaz, A.; Castellazzi, A. P-gate GaN HEMT gate-driver design for joint optimization of switching performance, freewheeling conduction and short-circuit robustness. In Proceedings of 2018 IEEE 30th International Symposium on Power Semiconductor Devices and ICs (ISPSD), Chicago, IL, USA, 13-17 May 2018.
  18. Sun, B.; Zhang, Z.; Andersen, M.A.E. Review of Resonant Gate Driver in Power Conversion. In Proceedings of 2018 International Power Electronics Conference (IPEC-Niigata 2018-ECCE Asia), Niigata, Japan, 20-24 May 2018.
  19. Lu, Y.; Zhu, J.; Sun, W.; Zhang, Y.; Hu, K.; Yu, Z.; Leng, J.;Cheng, S.; Zhang, S. A 600V high-side gate drive circuit with ultra-low propagation delay for enhancement mode GaN devices. In Proceedings of 2018 IEEE 30th International Symposium on Power Semiconductor Devices and ICs (ISPSD), Chicago, IL, USA, 13-17 May 2018.
  20. Yu, J.; Zhang, W.J.; Shorten, A.; Li, R.; Ng, W.T. A smart gate driver IC for GaN power transistors. In Proceedings of 2018 IEEE 30th International Symposium on Power Semiconductor Devices and ICs (ISPSD), Chicago, IL, USA, 13-17 May 2018.
  21. Achim Seidel; Bernhard Wicht; Integrated Gate Drivers Based on High-Voltage Energy Storing for GaN Transistors. IEEE Journal of Solid-State Circuits 2018, 53, 3446-3454, 10.1109/jssc.2018.2866948.
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