Effects of growth conditions on the acceptor activation of Mg-doped p-GaN

Ke, Wen−Cheng; Lee, Shuo-Jen; Chen, Shiow-Long; Kao, Chia-Yu; Houng, Wei-Chung

doi:10.1016/j.matchemphys.2012.01.128

Cited by 29 publications

(12 citation statements)

References 28 publications

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“…Because GaN material has aa negative differential mobility effect, a lower electric field can make the electrons in GaN material reach higher drift velocity. According to IMPATT current Equation (7), νs is the average drift velocity that carriers can reach in a semiconductor device, which explains why SiC/GaN IMPATT has a higher rf output current and frequency bandwidth. In a word, the rf electric field in the drift region can obtain a larger swing to achieve a lower value, and this electric field modulation is another mechanism to improve the performance of SiC/GaN IMPATT.…”

Section: Large-signal Simulation Results and Discussionmentioning

confidence: 99%

“…Before the rf power of IMPATT reaches saturation, it increases with the p-region concentration [5,6]. However, the practical fabrication of p-n junction GaN structures is challenging in IMPATT devices due to the difficulty of obtaining high concentrations of p-GaN because of the very low effective hole ionization rate [7]. Eventually, the voltage and current of this negative resistance device will be reduced, impairing the diode performance severely [8].…”

Section: Introductionmentioning

confidence: 99%

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Study on Electric Field Modulation and Avalanche Enhancement of SiC/GaN IMPATT Diode

Dai

Dang

et al. 2021

Electronics

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This paper proposes a 6H-materials silicon carbide (SiC)/gallium nitride (GaN) heterogeneous p-n structure to replace the GaN homogenous p-n junction to manufacture an impact-ionization-avalanche-transit-time (IMPATT) diode, and the performance of this 6H-SiC/GaN heterojunction single-drift-region (SDR) IMPATT diode is simulated at frequencies above 100 GHz. The performance parameters of the studied device were simulated and compared with the conventional GaN p-n IMPATT diode. The results show that the p-SiC/n-GaN IMPATT performance is significantly improved, and this is reflected in the enhanced characteristics in terms of operating frequency, rf power, and dc-rf conversion efficiency by the two mechanisms. One such characteristic that the new structure has an excessive avalanche injection of electrons in the p-type SiC region owing to the ionization characteristics of the SiC material, while another is a lower electric field distribution in the drift region, which can induce a higher electron velocity and larger current in the structure. The work provides a reference to obtain a deeper understanding of the mechanism and design of IMPATT devices based on wide-bandgap semiconductor materials.

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Section: Large-signal Simulation Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Study on Electric Field Modulation and Avalanche Enhancement of SiC/GaN IMPATT Diode

Dai

Dang

et al. 2021

Electronics

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“…In addition, the WPE of LED sample C demonstrated a 3.5% improvement in comparison with that of LED sample B, which is mainly attributed to the lower forward voltage of LED sample C. The Hall effect and x-ray photoemission spectroscopy (XPS) measurements were carried out in the following experiment to explain the improved performance for LED sample C. In order to clarify the mechanism of activation of p-type GaN at a relatively low temperature of 500°C in N 2 ambient, p-type GaN epitaxial wafers without MQWs active region were grown by MOCVD as follows: The epitaxial layers were done by sequentially depositing of a 30-nm-thick low-temperature GaN nucleation layer, a 2.0-μm-thick undoped GaN layer, a 0.6-μm-thick p-type GaN layer, and a 2.0-nm-thick InGaN strained layer on sapphire substrates. X-ray rocking curves showed that the full width at half maximums of the wafers was 299 arcsec for (0002) symmetric plane, indicating a good quality of the p-type GaN layers [ 21 ]. A 100-nm-thick ITO film was evaporated on the p-type GaN epitaxial layers by the electron beam evaporator.…”

Section: Resultsmentioning

confidence: 99%

Fabrication and characterization of GaN-based light-emitting diodes without pre-activation of p-type GaN

Wang

Zhang

2015

Nanoscale Res Lett

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We fabricated GaN-based light-emitting diodes (LEDs) without pre-activation of p-type GaN. During the fabrication process, a 100-nm-thick indium tin oxide film was served as the p-type contact layer and annealed at 500°C in N2 ambient for 20 min to increase its transparency as well as to activate the p-type GaN. The electrical measurements showed that the LEDs were featured by a lower forward voltage and higher wall-plug efficiency in comparison with LEDs using pre-activation of p-type GaN. We discussed the mechanism of activation of p-type GaN at 500°C in N2 ambient. Furthermore, x-ray photoemission spectroscopy examinations were carried out to study the improved electrical performances of the LEDs without pre-activation of p-type GaN.

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“…However, owing to the difficulty in the doping manufacturing process of p-GaN, a high-concentration of ionized holes cannot be formed [ 14 ], leading to a series of problems. Firstly, because of the overly low p-type region concentration and poor mobility characteristics, the electric field distribution in the avalanche region deviates from the ideal situation, deteriorating the impact-ionzation characteristics and inducing the device performance to decline.…”

Section: Introductionmentioning

confidence: 99%

Study of p-SiC/n-GaN Hetero-Structural Double-Drift Region IMPATT Diode

Dai

Dang

et al. 2021

Micromachines

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Nowadays, the immature p-GaN processes cannot meet the manufacturing requirements of GaN impact ionization avalanche transit time (IMPATT) diodes. Against this backdrop, the performance of wide-bandgap p-SiC/n-GaN heterojunction double-drift region (DDR) IMPATT diode is investigated in this paper for the first time. The direct-current (DC) steady-state, small-signal and large-signal characteristics are numerically simulated. The results show that compared with the conventional GaN single-drift region (SDR) IMPATT diode, the performance of the p-SiC/n-GaN DDR IMPATT proposed in this design, such as breakdown voltage, negative conductance, voltage modulation factor, radio frequency (RF) power and DC-RF conversion efficiency have been significantly improved. At the same time, the structure proposed in this design has a larger frequency bandwidth. Due to its greater potential in the RF power density, which is 1.97 MW/cm2 in this study, indicates that the p-SiC/n-GaN heterojunction provides new possibilities for the design and manufacture of IMPATT diode.

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Effects of growth conditions on the acceptor activation of Mg-doped p-GaN

Cited by 29 publications

References 28 publications

Study on Electric Field Modulation and Avalanche Enhancement of SiC/GaN IMPATT Diode

Study on Electric Field Modulation and Avalanche Enhancement of SiC/GaN IMPATT Diode

Fabrication and characterization of GaN-based light-emitting diodes without pre-activation of p-type GaN

Study of p-SiC/n-GaN Hetero-Structural Double-Drift Region IMPATT Diode

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