AlGaN/GaN epitaxy and technology

2010 ◽  
Vol 2 (1) ◽  
pp. 3-11 ◽  
Author(s):  
Patrick Waltereit ◽  
Wolfgang Bronner ◽  
Rüdiger Quay ◽  
Michael Dammann ◽  
Rudolf Kiefer ◽  
...  
Keyword(s):  
Output Power ◽  
Supply Voltage ◽  
Drain Current ◽  
High Electron Mobility Transistors ◽  
Base Station ◽  
High Electron ◽  
Power Performance ◽  
Power Added Efficiency ◽  
Electron Mobility Transistors ◽  
Conversion Efficiencies

We present an overview on epitaxial growth, processing technology, device performance, and reliability of our GaN high electron mobility transistors (HEMTs) manufactured on 3- and 4-in. SiC substrates. Epitaxy and processing are optimized for both performance and reliability. We use three different gate lengths, namely 500 nm for 1–6 GHz applications, 250 nm for devices between 6 and 18 GHz, and 150 nm for higher frequencies. The developed HEMTs demonstrate excellent high-voltage stability, high power performance, and large DC to RF conversion efficiencies for all gate lengths. On large gate width devices for base station applications, an output power beyond 125 W is achieved with a power added efficiency around 60% and a linear gain around 16 dB. Reliability is tested both under DC and RF conditions with supply voltage of 50 and 30 V for 500 and 250 nm gates, respectively. DC tests on HEMT devices return a drain current change of just about 10% under IDQ conditions. Under RF stress the observed change in output power density is below 0.2 dB after more than 1000 h for both gate length technologies.

scholarly journals High Efficiency AlN/GaN HEMTs for Q-Band Applications with an Improved Thermal Dissipation

2019 ◽  
Vol 28 (01n02) ◽  
pp. 1940003 ◽  
Author(s):  
Riad Kabouche ◽  
Romain Pecheux ◽  
Kathia Harrouche ◽  
Etienne Okada ◽  
Farid Medjdoub ◽  
...  
Keyword(s):  
High Efficiency ◽  
Drain Current ◽  
High Electron Mobility Transistors ◽  
Thermal Dissipation ◽  
High Electron ◽  
Power Performance ◽  
Power Added Efficiency ◽  
Carbon Doped ◽  
Electron Mobility Transistors ◽  
Band Power

In this paper, we demonstrate Q-band power performance of carbon doped AlN/GaN high electron mobility transistors (HEMTs) using a deep sub-micrometer gate length (120 nm). With a maximum drain current density ID of 1.5 A/mm associated to a high electron confinement and an extrinsic transconductance gm of 500 mS/mm, this structure shows excellent electrical characteristics. A maximum oscillation frequency fmax of 242 GHz has been observed. As a result, a state-of-the-art combination at 40 GHz of output power density (POUT = 7 W/mm) and power added efficiency (PAE) of 52% up to VDS = 25V has been obtained. The achievement of such outstanding performance is attributed to the reduced thermal resistance (RTH) as compared to the commonly used double heterostructure by means of Raman thermography.

MBE-Grown AlGaN/GaN HEMTs on SiC

2004 ◽  
Vol 14 (03) ◽  
pp. 732-737 ◽  
Author(s):  
SIDDHARTH RAJAN ◽  
ARPAN CHAKRABORTY ◽  
UMESH K. MISHRA ◽  
CHRISTIANE POBLENZ ◽  
PATRICK WALTEREIT ◽  
...  
Keyword(s):  
Output Power ◽  
High Electron Mobility Transistors ◽  
Layer Growth ◽  
Carbon Doping ◽  
Limiting Factor ◽  
High Electron ◽  
Nucleation Layer ◽  
Power Added Efficiency ◽  
Electron Mobility Transistors ◽  
Gan Hemts

We report on the development of AlGaN/GaN high-electron mobility transistors (HEMTs) grown on SiC using plasma-assisted molecular beam epitaxy (MBE). In this work, we show that performance comparable to state-of-the-art AlGaN/GaN HEMTs can be achieved using MBE-grown material. Buffer leakage was an important limiting factor for these devices. The use of either carbon-doped buffers, or low Al/N ratio in the nucleation layer growth were effective in reducing buffer leakage. Studies varying the thickness and concentration of the carbon doping were carried out to determine the effect of different carbon doping profiles on the insulating and dispersive properties of buffers, On devices without field plates, at 4 GHz an output power density of 12 W/mm was obtained with a power-added efficiency (PAE) of 46 % and gain of 14 dB. 15.6 W/mm with PAE of 56 % was obtained from these devices after field-plating. Two-tone linearity measurements of these devices were also carried out. At a C/I 3 level of 30 dBc, the devices measured had an output power of 1.9 W/mm with a PAE of 53 %. The effect of the Al/N ratio in the AlN nucleation layer on buffer leakage was studied. N -rich conditions yielded highly insulating GaN buffers without carbon doping. At 4 GHz, devices without field plates delivered 4.8 W/mm with a PAE of 62 %. At a higher drain bias (50 V), 8.1 W/mm with a PAE of 38 % was achieved.

Fabrication and characterization of AlGaN/GaN HEMTs with high power gain and efficiency at 8 GHz

2021 ◽  
Vol 42 (12) ◽  
pp. 122802
Author(s):  
Quan Wang ◽  
Changxi Chen ◽  
Wei Li ◽  
Yanbin Qin ◽  
Lijuan Jiang ◽  
...  
Keyword(s):  
High Power ◽  
Electron Mobility ◽  
Drain Current ◽  
High Electron Mobility Transistors ◽  
High Electron ◽  
Power Gain ◽  
High Electron Mobility ◽  
Power Added Efficiency ◽  
Electron Mobility Transistors ◽  
Dimensional Electron Gas

Abstract State-of-the-art AlGaN/GaN high electron mobility structures were grown on semi-insulating 4H-SiC substrates by MOCVD and X-band microwave power high electron mobility transistors were fabricated and characterized. Hall mobility of 2291.1 cm2/(V·s) and two-dimensional electron gas density of 9.954 × 1012 cm–2 were achieved at 300 K. The HEMT devices with a 0.45-μm gate length exhibited maximum drain current density as high as 1039.6 mA/mm and peak extrinsic transconductance of 229.7 mS/mm. The f T of 30.89 GHz and f max of 38.71 GHz were measured on the device. Load-pull measurements were performed and analyzed under (–3.5, 28) V, (–3.5, 34) V and (–3.5, 40) V gate/drain direct current bias in class-AB, respectively. The uncooled device showed high linear power gain of 17.04 dB and high power-added efficiency of 50.56% at 8 GHz when drain biased at (–3.5, 28) V. In addition, when drain biased at (–3.5, 40) V, the device exhibited a saturation output power density up to 6.21 W/mm at 8 GHz, with a power gain of 11.94 dB and a power-added efficiency of 39.56%. Furthermore, the low f max/f T ratio and the variation of the power sweep of the device at 8 GHz with drain bias voltage were analyzed.

AlGaN Channel HEMT with Extremely High Breakdown Voltage

2011 ◽  
Vol 1324 ◽  
Author(s):  
Takuma Nanjo ◽  
Misaichi Takeuchi ◽  
Akifumi Imai ◽  
Yousuke Suzuki ◽  
Muneyoshi Suita ◽  
...  
Keyword(s):  
Breakdown Voltage ◽  
Drain Current ◽  
High Electron Mobility Transistors ◽  
Low Noise ◽  
Low Noise Amplifiers ◽  
High Electron ◽  
Field Plate ◽  
Electron Mobility Transistors ◽  
Doping Technique ◽  
Resistive Source

ABSTRACTA channel layer substitution of a wider bandgap AlGaN for a conventional GaN in high electron mobility transistors (HEMTs) is an effective method of enhancing the breakdown voltage. Wider bandgap AlGaN, however, should also increase the ohmic contact resistance. Si ion implantation doping technique was utilized to achieve sufficiently low resistive source/drain contacts. The fabricated AlGaN channel HEMTs with the field plate structure demonstrated good pinch-off operation with sufficiently high drain current density of 0.5 A/mm without noticeable current collapse. The obtained maximum breakdown voltages was 1700 V in the AlGaN channel HEMT with the gate-drain distance of 10 μm. These remarkable results indicate that AlGaN channel HEMTs could become future strong candidates for not only high-frequency devices such as low noise amplifiers but also high-power devices such as switching applications.

scholarly journals Development of Catalytic-CVD SiNx Passivation Process for AlGaN/GaN-on-Si HEMTs

Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 842 ◽  
Author(s):  
Myoung-Jin Kang ◽  
Hyun-Seop Kim ◽  
Ho-Young Cha ◽  
Kwang-Seok Seo
Keyword(s):  
Chemical Vapor ◽  
Drain Current ◽  
High Electron Mobility Transistors ◽  
Breakdown Field ◽  
High Electron ◽  
Electron Mobility Transistors ◽  
Current Collapse ◽  
Passivation Process ◽  
Gan On Si ◽  
Sinx Film

We optimized a silicon nitride (SiNx) passivation process using a catalytic-chemical vapor deposition (Cat-CVD) system to suppress the current collapse phenomenon of AlGaN/GaN-on-Si high electron mobility transistors (HEMTs). The optimized Cat-CVD SiNx film exhibited a high film density of 2.7 g/cm3 with a low wet etch rate (buffered oxide etchant (BOE) 10:1) of 2 nm/min and a breakdown field of 8.2 MV/cm. The AlGaN/GaN-on-Si HEMT fabricated by the optimized Cat-CVD SiNx passivation process, which had a gate length of 1.5 μm and a source-to-drain distance of 6 μm, exhibited the maximum drain current density of 670 mA/mm and the maximum transconductance of 162 mS/mm with negligible hysteresis. We found that the optimized SiNx film had positive charges, which were responsible for suppressing the current collapse phenomenon.

RF Power Performance Evaluation of Surface Channel Diamond MESFET

2009 ◽  
Vol 1203 ◽  
Author(s):  
Maria Cristina Rossi ◽  
Paolo Calvani ◽  
Gennaro Conte ◽  
Vittorio Camarchia ◽  
Federica Cappelluti ◽  
...  
Keyword(s):  
Output Power ◽  
Threshold Voltage ◽  
Polycrystalline Diamond ◽  
Drain Current ◽  
Rf Power ◽  
Power Performance ◽  
Power Devices ◽  
Large Signal ◽  
Device Structure ◽  
Power Added Efficiency

AbstractLarge-signal radiofrequency performances of surface channel diamond MESFET fabricated on hydrogenated polycrystalline diamond are investigated. The adopted device structure is a typical coplanar two-finger gate layout, characterized in DC by an accumulation-like behavior with threshold voltage Vt ∼ 0-0.5 V and maximum DC drain current of 120 mA/mm. The best radiofrequency performances (in terms of fT and fmax) were obtained close to the threshold voltage. Realized devices are analyzed in standard class A operation, at an operating frequency of 2 GHz. The MESFET devices show a linear power gain of 8 dB and approximately 0.2 Wmm RF output power with 22% power added efficiency. An output power density of about 0.8 W/mm can be then extrapolated at 1 GHz, showing the potential of surface channel MESFET technology on polycrystalline diamond for microwave power devices.

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