De-Feng Lin
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
De-Feng Lin has a total of 25 co-authors. Here are the top co-authors by number of shared publications:
- Lifang Jia
Laboratory of Solid State Optoelectronics Information Technology, Institute of Semiconductors, CAS, Beijing 100083, China
3 shared publications - Yun Zhang
Chinese Academy of Sciences, Institute of Semiconductors, Beijing, CHINA
3 shared publications - Zhe Cheng
Laboratory of Solid State Optoelectronics Information Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
3 shared publications C. Feng
Materials Science Center, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, P.R. China
2 shared publicationsC.M. Wang
Materials Science Center, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, P.R. China
2 shared publicationsH. Chen
Materials Science Center, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, P.R. China
2 shared publications
Latest Publications
- Open Access
- 28 December 2021
- Published by MDPI AG in Micromachines
- Vol. 13 (1) , 40
An Experimental and Theoretical Study of Impact of Device Parameters on Performance of AlN/Sapphire-Based SAW Temperature Sensors
The impact of device parameters, including AlN film thickness (hAlN), number of interdigital transducers (NIDT), and acoustic propagation direction, on the performance of c-plane AlN/sapphire-based SAW temperature sensors with an acoustic wavelength (λ) of 8 μm, was investigated. The results showed that resonant frequency (fr) decreased linearly, the quality factor (Q) decreased and the electromechanical coupling coefficient increased for all the sensors with temperature increasing from −50 to 250 °C. The temperature coefficients of frequency (TCFs) of sensors on AlN films with thicknesses of 0.8 and 1.2 μm were −65.57 and −62.49 ppm/°C, respectively, indicating that a reduction in hAlN/λ favored the improvement of TCF. The acoustic propagation direction and NIDT did not obviously impact the TCF of sensors, but they significantly influenced the Q and of the sensors. At all temperatures measured, sensors along the a-direction exhibited higher fr, Q and than those along the m-direction, and sensors with NIDT of 300 showed higher Q and values than those with NIDT of 100 and 180. Moreover, the elastic stiffness of AlN was extracted by fitting coupling of modes (COM) model simulation to the experimental results of sensors along different directions considering Euler transformation of material parameter-tensors. The higher fr of the sensor along the a-direction than that along the m-direction can be attributed to its larger elastic stiffness c11, c22, c44, and c55 values.- 28 December 2021
- Published by MDPI AG in Micromachines
- Vol. 13 (1) , 40
Open AccessAn Experimental and Theoretical Study of Impact of Device Parameters on Performance of AlN/Sapphire-Based SAW Temperature Sensors
The impact of device parameters, including AlN film thickness (hAlN), number of interdigital transducers (NIDT), and acoustic propagation direction, on the performance of c-plane AlN/sapphire-based SAW temperature sensors with an acoustic wavelength (λ) of 8 μm, was investigated. The results showed that resonant frequency (fr) decreased linearly, the quality factor (Q) decreased and the electromechanical coupling coefficient increased for all the sensors with temperature increasing from −50 to 250 °C. The temperature coefficients of frequency (TCFs) of sensors on AlN films with thicknesses of 0.8 and 1.2 μm were −65.57 and −62.49 ppm/°C, respectively, indicating that a reduction in hAlN/λ favored the improvement of TCF. The acoustic propagation direction and NIDT did not obviously impact the TCF of sensors, but they significantly influenced the Q and of the sensors. At all temperatures measured, sensors along the a-direction exhibited higher fr, Q and than those along the m-direction, and sensors with NIDT of 300 showed higher Q and values than those with NIDT of 100 and 180. Moreover, the elastic stiffness of AlN was extracted by fitting coupling of modes (COM) model simulation to the experimental results of sensors along different directions considering Euler transformation of material parameter-tensors. The higher fr of the sensor along the a-direction than that along the m-direction can be attributed to its larger elastic stiffness c11, c22, c44, and c55 values. - Open Access
- 30 July 2021
- Published by MDPI AG in Applied Sciences
- Vol. 11 (15) , 7057
Design and Switching Characteristics of Flip-Chip GaN Half-Bridge Modules Integrated with Drivers
Half-bridge modules with integrated GaN high electron mobility transistors (HEMTs) and driver dies were designed and fabricated in this research. Our design uses flip-chip technology for fabrication, instead of more generally applied wire bonding, to reduce parasitic inductance in both the driver-gate and drain-source loops. Modules were prepared using both methods and the double-pulse test was applied to evaluate and compare their switching characteristics. The gate voltage () waveform of the flip-chip module showed no overshoot during the turn-on period, and a small oscillation during the turn-off period. The probabilities of gate damage and false turn-on were greatly reduced. The inductance in the drain-source loop of the module was measured to be 3.4 nH. The rise and fall times of the drain voltage () were 12.9 and 5.8 ns, respectively, with an overshoot of only 4.8 V during the turn-off period under = 100 V. These results indicate that the use of flip-chip technology along with the integration of GaN HEMTs with driver dies can effectively reduce the parasitic inductance and improve the switching performance of GaN half-bridge modules compared to wire bonding.- 30 July 2021
- Published by MDPI AG in Applied Sciences
- Vol. 11 (15) , 7057
Open AccessDesign and Switching Characteristics of Flip-Chip GaN Half-Bridge Modules Integrated with Drivers
Half-bridge modules with integrated GaN high electron mobility transistors (HEMTs) and driver dies were designed and fabricated in this research. Our design uses flip-chip technology for fabrication, instead of more generally applied wire bonding, to reduce parasitic inductance in both the driver-gate and drain-source loops. Modules were prepared using both methods and the double-pulse test was applied to evaluate and compare their switching characteristics. The gate voltage () waveform of the flip-chip module showed no overshoot during the turn-on period, and a small oscillation during the turn-off period. The probabilities of gate damage and false turn-on were greatly reduced. The inductance in the drain-source loop of the module was measured to be 3.4 nH. The rise and fall times of the drain voltage () were 12.9 and 5.8 ns, respectively, with an overshoot of only 4.8 V during the turn-off period under = 100 V. These results indicate that the use of flip-chip technology along with the integration of GaN HEMTs with driver dies can effectively reduce the parasitic inductance and improve the switching performance of GaN half-bridge modules compared to wire bonding. - Open Access
- 27 May 2021
- Published by MDPI AG in Micromachines
- Vol. 12 (6) , 617
E/D-Mode GaN Inverter on a 150-mm Si Wafer Based on p-GaN Gate E-Mode HEMT Technology
AlGaN/GaN E/D-mode GaN inverters are successfully fabricated on a 150-mm Si wafer. P-GaN gate technology is applied to be compatible with the commercial E-mode GaN power device technology platform and a systematic study of E/D-mode GaN inverters has been conducted with detail. The key electrical characters have been analyzed from room temperature (RT) to 200 °C. Small variations of the inverters are observed at different temperatures. The logic swing voltage of 2.91 V and 2.89 V are observed at RT and 200 °C at a supply voltage of 3 V. Correspondingly, low/high input noise margins of 0.78 V/1.67 V and 0.68 V/1.72 V are observed at RT and 200 °C. The inverters also demonstrate small rising edge time of the output signal. The results show great potential for GaN smart power integrated circuit (IC) application.
- 27 May 2021
- Published by MDPI AG in Micromachines
- Vol. 12 (6) , 617
Open AccessE/D-Mode GaN Inverter on a 150-mm Si Wafer Based on p-GaN Gate E-Mode HEMT Technology
AlGaN/GaN E/D-mode GaN inverters are successfully fabricated on a 150-mm Si wafer. P-GaN gate technology is applied to be compatible with the commercial E-mode GaN power device technology platform and a systematic study of E/D-mode GaN inverters has been conducted with detail. The key electrical characters have been analyzed from room temperature (RT) to 200 °C. Small variations of the inverters are observed at different temperatures. The logic swing voltage of 2.91 V and 2.89 V are observed at RT and 200 °C at a supply voltage of 3 V. Correspondingly, low/high input noise margins of 0.78 V/1.67 V and 0.68 V/1.72 V are observed at RT and 200 °C. The inverters also demonstrate small rising edge time of the output signal. The results show great potential for GaN smart power integrated circuit (IC) application.
- 28 September 2011
- Published by EDP Sciences in The European Physical Journal Applied Physics
- Vol. 56 (1) , 10101
Low temperature characteristics of AlGaN/GaN high electron mobility transistors
The I-V characteristics of AlGaN/GaN high electron mobility transistors in the temperature range between 100 K and 300 K are studied. It is found that both the maximum drain-source current and transconductance decrease with the increase of temperature. Decrease of the electron mobility with increasing temperature is considered to be the main cause for that condition. The threshold voltage shows a forward shift, which can be explained by the increase of Schottky barrier with increasing temperature. It is found that at VGS = 0 V the drain-source current reduces with the ascending temperature, which should be due to the variation of the electron mobility with the temperature. While at VGS = −5 V the drain-source current is found to increase with the ascending temperature, it is suggested to be caused by the positive temperature coefficient of the electron transport in the depleted region.
- 28 September 2011
- Published by EDP Sciences in The European Physical Journal Applied Physics
- Vol. 56 (1) , 10101
Low temperature characteristics of AlGaN/GaN high electron mobility transistors
The I-V characteristics of AlGaN/GaN high electron mobility transistors in the temperature range between 100 K and 300 K are studied. It is found that both the maximum drain-source current and transconductance decrease with the increase of temperature. Decrease of the electron mobility with increasing temperature is considered to be the main cause for that condition. The threshold voltage shows a forward shift, which can be explained by the increase of Schottky barrier with increasing temperature. It is found that at VGS = 0 V the drain-source current reduces with the ascending temperature, which should be due to the variation of the electron mobility with the temperature. While at VGS = −5 V the drain-source current is found to increase with the ascending temperature, it is suggested to be caused by the positive temperature coefficient of the electron transport in the depleted region.
- 18 August 2011
- Published by EDP Sciences in The European Physical Journal Applied Physics
- Vol. 55 (3) , 30104
The transport mechanism of gate leakage current in AlGaN/GaN high electron mobility transistors
The temperature dependence of the I-V characteristics on Au/Ni-HEMT Schottky contacts was measured and analyzed. Large deviations from the thermionic emission and thermionic-field emission model were observed in the I-V-T characteristics. The thin surface barrier model only fits the measured curves in the high bias region, but deviates drastically in the low bias region. Using a revised thin surface barrier model, the calculated curves match well with the measured curves. It is also found that tunneling emission model is the dominant current transport mechanism at low temperature, yet thermionic-field emission model is the dominant current transport mechanism at high temperature.
- 18 August 2011
- Published by EDP Sciences in The European Physical Journal Applied Physics
- Vol. 55 (3) , 30104
The transport mechanism of gate leakage current in AlGaN/GaN high electron mobility transistors
The temperature dependence of the I-V characteristics on Au/Ni-HEMT Schottky contacts was measured and analyzed. Large deviations from the thermionic emission and thermionic-field emission model were observed in the I-V-T characteristics. The thin surface barrier model only fits the measured curves in the high bias region, but deviates drastically in the low bias region. Using a revised thin surface barrier model, the calculated curves match well with the measured curves. It is also found that tunneling emission model is the dominant current transport mechanism at low temperature, yet thermionic-field emission model is the dominant current transport mechanism at high temperature.