Gallium nitride based high power heterojunction field effect transistors: process development and present status at UCSB

Keller, S.; Wu, Yifeng; Parish, Giacinta; Ziang, Naiqian; Xu, Jin; Keller, B.P.; DenBaars, Steven P.; Mishra, Umesh K.

doi:10.1109/16.906450

Cited by 181 publications

(89 citation statements)

References 40 publications

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“…As a reference, unintentionally doped (UID) GaN on sapphire prepared by MOCVD exhibits a lightly n-type background concentration of about 5 × 10 16 cm −3 with a mobility of 600 cm 2 V -1 s -1 . [ 17 ] The sheet resistance of a 90-nm thick GaN NM is estimated to be around 20 KΩ if the NM has the identical transport property. However, all the 140 nm-thick and thinner membranes on either SiO 2 /Si or sapphire prepared in our lab are found to be highly resistive by Van der Pauw method.…”

Section: Uv-assisted Hall Measurementmentioning

confidence: 99%

Single Crystal Gallium Nitride Nanomembrane Photoconductor and Field Effect Transistor

Xiong

Park

Song

et al. 2014

Adv Funct Materials

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We report in this work the fabrication of single crystal GaN nanomembranes, with a thickness as low as 50 nm. Large area (≥5 mm × 5 mm) GaN membranes are produced by electrochemical etching (ECE) with a special high-conductivity sacrifi cial underlayer. Large-area, crackfree transfer of GaN NMs have been performed onto metal, glass, and polymer target substrates. The transport properties of freestanding GaN nanomembranes are analyzed using UV-assisted Hall measurements. The interaction of the carriers with the surface electronic states are investigated by the intensity dependence of the photoconductor gain, and by the temperature-dependent measurements of photocurrent decay. The transport property of GaN NM, down to a thickness of 90 nm, remains very comparable to that from much thicker GaN structures. Enhancement-mode fi eld effect transistors (FETs) have been fabricated and demonstrated on a SiO 2 / Si(001) wafer, suggesting that GaN nanomembranes can be a new candidate for fl exible electronics requiring high power and high-frequency. Results and Discussion Nanomembrane FabricationThe principle of using an ECE process to selectively remove underlying GaN sacrifi cial layers has been described before. [ 12,13 ] Multi-layered GaN structures having nanomembrane layers (50 to 500 nm thick) on top of heavily-doped ( n ≈ 1 × 10 19 cm −3 ) GaN sacrifi cial layers were grown by metal-organic chemical vapor deposition (MOCVD) process on sapphire. To obtain large-area NM within a reasonable time, a periodic array of via holes were created such that the undercut etching can proceeds uniformly around these openings. The via-holes are squares with a dimension of 10 µm and a diagonal periodicity of 25, 50, and 100 µm. These holes were created by Cl-based inductively coupled plasma (ICP) etching to expose the sacrifi cial layer. The photoresist (Shipley S1827) used during the Cl-ICP etching was retained to protect the front surface of the membrane during ECE. The nanomembrane layers became detached from the substrate once the undercut regions around each opening coalesce with the adjacent ones. GaN NMs were cleaned by rinsing sequentially in DI water, acetone and isopropyl-alcohol (IPA). After cleaning, they were transferred on to other substrates Single Crystal Gallium Nitride Nanomembrane Photoconductor and Field Effect Transistor Kanglin Xiong , Sung Hyun Park , Jie Song , Ge Yuan , Danti Chen , Benjamin Leung , and Jung Han * Large-area, free-standing and single-crystalline GaN nanomembranes are prepared by electrochemical etching from epitaxial layers. As-prepared nanomembranes are highly resistive but can become electronically active upon optical excitation, with an excellent electron mobility. The interaction of excited carriers with surface states is investigated by intensity-dependent photoconductivity gain and temperature-dependent photocurrent decay. Normally off enhancement-type GaN nanomembrane MOS transistors are demonstrated, suggesting that GaN could be used in fl exible electronics for high power and hig...

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Section: Uv-assisted Hall Measurementmentioning

confidence: 99%

Single Crystal Gallium Nitride Nanomembrane Photoconductor and Field Effect Transistor

Xiong

Park

Song

et al. 2014

Adv Funct Materials

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“…The reduction of drain current and increase in the knee voltage in AlGaN/GaN HEMTs under RF conditions caused by the presence of both bulk and surface electron traps have been discussed in many recent publications devoted to GaN devices [11]- [13]. Ultimately they lead to a reduced RF output power and poor efficiency.…”

Section: Device Structure and Fabricationmentioning

confidence: 99%

AlGaN/GaN HEMTs---operation in the K-band and above

Smorchkova¹,

Wójtowicz²,

Sandhu³

et al. 2003

IEEE Trans. Microwave Theory Techn.

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“…The rapid development of the RF power electronics requires the introduction of wide bandgap material due to its potential in high output power density, high operation voltage and high input impedance [3]. A variety of power amplifier technologies are competing for market share, such as Si lateral-diffused metal-oxide-semiconductors (LDMOS) and bipolar transistors, GaAs metalsemiconductor field-effect transistors (MESFETs), GaAs (or GaAs/InGaP) heterojunction bipolar transistors, SiC MESFETs, and GaN high-electron mobility transistors (HEMTs) [4]. Compared to other compound III-V semiconductor materials, gallium nitride (GaN) provides some superior material characteristics including wide bandgap, high breakdown field, high thermal conductivity, and high saturated velocity [2].…”

Section: Introductionmentioning

confidence: 99%

Design of high power S-band GaN MMIC power amplifiers for WiMAX applications

Cengiz

Kelekçi

Ar'can

et al. 2011

2011 XXXth URSI General Assembly and Scientific Symposium

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This paper reports two different S band GaN MMIC PA designs for WiMAX applications. First PA has a 42.6 dBm output power with a 55%PAE @ 3.5 GHz and 16 dB small signal gain in the 3.2-3.8 GHz frequency range. When two of these MMICs were combined by using off-chip Lange Couplers, 45.3 dBm output power with a 45%PAE @3.5Ghz and 16 dB small signal gain were obtained with less than 0.2 dB gain ripple in the 3.3-3.8 GHz frequency range.

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Gallium nitride based high power heterojunction field effect transistors: process development and present status at UCSB

Cited by 181 publications

References 40 publications

Single Crystal Gallium Nitride Nanomembrane Photoconductor and Field Effect Transistor

Single Crystal Gallium Nitride Nanomembrane Photoconductor and Field Effect Transistor

AlGaN/GaN HEMTs---operation in the K-band and above

Design of high power S-band GaN MMIC power amplifiers for WiMAX applications

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