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This paper presents the measured results of two circuits fabricated with a millimeter wave 100 nm Gallium Nitride on Silicon (GaN/Si) process. The first circuit is a 27-34 GHz power amplifier, presenting 6 W of output power in pulsed operation and 5.6 W in CW operation. The second circuit, using exactly the same process, is a 8-12 GHz Low Noise Amplifier presenting 1.3 dB noise figure from 11 to 13...
VAR compensators (VARComps) are devices that produce reactive power in AC electrical systems. Electronic inverter circuits can supply currents that are at 90° to the grid voltage to supply reactive power Q. Since no active power P is delivered to the grid, these devices appear as a two terminal device similar to a capacitor or inductor. A VARComp was developed for this purpose. In this research, Si...
A RF leakage phenomenon in GaN HEMTs on Si substrates is analyzed with taking atomic diffusion at buffer/substrate interface into consideration, and a novel physical model of RF leakage based on the analysis is proposed. The Al or Ga atoms are moved from buffer layer to Si substrate at an epitaxial growth. Then, an acceptor layer with high hole density and an inversion layer with high electron density...
Due to the superior characteristics of GaN to Si, they can be utilized to drastically increase the efficiency and minimize the size of power converter system. However, there has been a critical issue of the so-called current collapse where ON-state resistance is increased once GaN transistor is exposed to high voltage. From the temperature dependence of the switching characteristics of an enhancement-mode...
A simple and effective method to grow GaN on Si substrates has been achieved. The method that GaN comes out from a submicron and deep hole with nearly zero dislocations above the mask is demonstrated. This work proves that reducing the epitaxy area by using mask and increasing the depth to width ratio of pattern contribute to filtering the dislocations and improving the quality of GaN.
In recent years, GaN power HEMTs are gaining acceptance in power electronic applications. However, the implementation of Class D audio power amplifiers application using GaN power HEMTs has not been widely studied. This paper studies the performance of two open-loop 25 W Class D audio power amplifiers with GaN and silicon output stages using a Pulse Density Modulation (PDM) scheme. Comparisons of...
In this work, a high performance AlGaN/GaN power diode featuring MIS-gated hybrid anode (MG-HAD) with ultralow forward turn-on voltage (VT) and low reverse leakage current was experimentally demonstrated. By accurately designing the recessing depth in the MIS-gate region, a record low VT of 0.2 V for GaN power diode was obtained in the MG-HAD with 4-nm recessed-barrier-thickness. Meanwhile, the device...
In this work, the electrical properties of AlGaN/GaN heterostructure grown on Si substrate with low-temperature AlN (LT-AlN) interlayers were investigated. Hall effect measurement was used to test the electrical properties of AlGaN/GaN heterostructure in all samples with different LT-AlN thickness. It is showed that the thickness of low-temperature AlN interlayers in the bufferlayer obviously effect...
A monolithic diode laser on (001)Si is useful for silicon photonics. Ga (Al, In)N nanowires can be grown catalyst-free on silicon and other substrates [1]. The diameter of individual nanowires in an array and the array density can be varied over wide ranges. Single or multiple InGaN disks can be inserted in Ga(Al)N nanowires and the alloy composition in the disk can be varied to tune the luminescence...
III-nitride nanowires and disk-in-nanowire heterostructures grown on silicon substrates have been used to realize light emitting diodes (LEDs) [1, 2] and diode lasers [3, 4]. We have recently demonstrated edge-emitting disk-in-nanowire diode lasers, in which the gain region consists of multiple InxGa1−xN (0.3≤×≤0.85)/GaN disks and the emission wavelength varied in the range of 0.53 to 1.2 μm [4]....
In this paper, a Two-Switch forward converter using enhancement mode Gallium Nitride transistors (GaN FETs) operating in CCM is designed for low power and high frequency applications. This topology provides a galvanic isolated, simple and efficient approach which will be suitable to use in battery charge circuits. The performance of the converter is evaluated using Si MOSFETs and GaN FETs. Comparison...
The power MOSFET wafers which base on silicon substrates are almost reaching end of road, lacking on both performance and cost. It was widely predicted in the industry that next generation wafers should come from Gallium Nitride (GaN) substrate. This new material is expected to be the dominant technology due to its competitive in almost all aspects. Many high power device providers are making deep...
This work demonstrates the suitability of AlGaN/GaN-on-Si Schottky diodes in a non-isolated buck converter for LED applications. To the authors' knowledge, this is the first time that AlGaN/GaN-on-Si Schottky diodes have been employed as flyback diodes in a non-isolated buck converter. First the diodes are specifically developed and characterized. Afterwards the diodes are tested in an advanced non-isolated...
In this work we demonstrate, for the first time, the advantages of GaN HEMTs on bulk GaN substrates over similarly processed devices on Sapphire and Silicon substrates, intended for power applications, in terms of on-state and off-state operation as well as reliability, where self-heating, off-state leakage, and trapping effects are minimal. MIS-HEMTs with breakdown voltage of ∼670 V and off-state...
Wide-bandgap power devices such as those made from silicon carbide (SiC) and gallium nitride (GaN) realize fast switching and it helps to increase the efficiency of power conversion. This report experimentally compares static and dynamic characteristics of wide-bandgap power switching transistors; SiC MOSFET and cascode GaN transistor, and focuses on their characteristics of electromagnetic interference...
Automotive point-of-load (POL) dc-dc converters have wide input voltage range and strict EMI limitation requirements. In order to avoid the AM band interference, the switching frequency is desired to be above 2 MHz. The buck converter is widely used for this application but it has low efficiency at high switching frequency and poor EMI performance due to high dv/dt slew rate. A new active-clamp buck...
As the technology on wide bandgap materials such as gallium-nitride (GaN) has advanced rapidly, commercial GaN power devices with satisfying performance are available now. It is widely-known that GaN-based switching devices have several advantages over traditional Si-based switching devices, such as lower ON-resistance, faster switching speed, better thermal conductivity, and smaller size. However,...
Switching loss is an important and often the dominant source of converter losses. While soft-switching can greatly reduce the impact of switching loss, hard-switching is often preferred due to the simplicity of design, control, and implementation. Wide bandgap (WBG) semiconductors such as gallium nitride (GaN) and silicon carbide (SiC) have greatly reduced switching losses due to faster transition...
The wide band-gap Silicon Carbide (SiC) and gallium nitride (GaN) materials based semiconductor devices have attracted tremendous attentions in modern power electronics applications. They provide much higher switching frequency and higher junction temperature than silicon power devices, thus to significantly decrease the system volume and weight, especially on passive components. In this paper, the...
In this paper, an ultra-low inductance power cell design for a 3L-ANPC based on 650 V GaN HEMT devices is presented. The 3L-ANPC topology with GaN HEMT devices and the selected modulation scheme suitable for wide-bandgap (WBG) devices are presented. The commutation loops, which are the main contributors to voltage overshoots and increase of switching losses, are discussed. The ultra-low inductance...
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