An Al/sub 0.3/Ga/sub 0.7/N/GaN undoped channel heterostructure field effect transistor with F/sub max/ of 107 GHz

Li, R.; Cai, Shiwei; Wong, L. W.; Chen, Y.; Wang, K.L.; Smith, R.P.; Martin, Suzanne; Boutros, K. S.; Redwing, Joan M.

doi:10.1109/55.772364

Cited by 73 publications

(26 citation statements)

References 16 publications

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“…Nevertheless, with improved epitaxial growth techniques remarkable progress has been made in recent years, resulting in the development of UV GaN/AlGaN quantumwell light-emitting diodes 1 and high-power high-frequency electronic devices such as AlGaN/GaN heterostructure field-effect transistors (HFETs) with power densities up to 9.1 W mm 1 at 7.4 GHz. 2,3 High-brightness bluelightemitting diodes (LEDs) and laser diodes have been realized using InGaN as active medium. 4 -6 Metal-organic chemical vapour deposition (MOCVD) is currently the most accepted technique for the growth of high-quality optoelectronic and electronic device structures, 1 -6 although molecular beam epitaxy (MBE) has shown some success recently in the growth of electronic AlGaN/GaN device structures on GaN substrates.…”

Section: Introductionmentioning

confidence: 99%

Raman spectroscopy of GaN, AlGaN and AlN for process and growth monitoring/control

Kuball

2001

Surface & Interface Analysis

341

127

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The use of micro-Raman spectroscopy to monitor non-invasively GaN, AlGaN and AlN material parameters for process and growth monitoring/control is demonstrated. Concepts to determine the crystalline quality, the stress, the free carrier concentration, the aluminium composition and the temperature from the Raman modes are reviewed. Raman monitoring of processing and growth is illustrated on selected examples: the high-temperature processing of ion-implanted and non-implanted GaN layers, the Raman monitoring of AlGaN/GaN heterostructure field-effect transistors and the in situ Raman monitoring of GaN growth at elevated temperatures. Ultraviolet Raman spectroscopy has been employed to characterize material properties of GaN surface layers and GaN/AlGaN interfaces. Raman mapping is illustrated on bulk AlN crystals to investigate stress fields related to growth striations and defects.

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Section: Introductionmentioning

confidence: 99%

Raman spectroscopy of GaN, AlGaN and AlN for process and growth monitoring/control

Kuball

2001

Surface & Interface Analysis

341

127

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“…Interest in this material has been high-frequency transistors due to its high electron saturation velocity, high critical field, and high stability. AIGaN/GaN High Mobility Electron Transistors (HEMTs) with improved sheet carrier densities and two-dimensional nobilities have been reported [1][2][3][4][5][6]. Progress in nitride-based material quality and device processing has motivated the development of bipolar transistors which have demonstrated, in GaAs and InP systems, better linearity over the field effect transistor counterpart.…”

mentioning

confidence: 99%

Effect of Mg ionization efficiency on performance of Npn AlGaN/GaN heterojunction bipolar transistors

Monier¹,

Pearton²,

Chang³

et al. 2000

Applied Physics Letters

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A drift-diffusion transport model has been used to examine the performance capabilities of AIGaN/GaN Npn heterojunction bipolar transistors (HBTs). The Gumrnel plot from the first GaN-based HBT structure recently demonstrated is adjusted with simulation by using experimental mobility and lifetime reported in the literature. Numerical results have been explored to study the effect of the p-type Mg doping and its incomplete ionization in the base.The high base resistance induced by the deep acceptor level is found to be the cause of limiting current gain values. Increasing the operating temperature of the device activates more carriers in the base. An improvement of the simulated current gain by a factor of 2 to 4 between 25 and 300"C agrees well with the reported experimental results. A preliminary analysis of high frequency characteristics indicates substantial progress of predicted rf performances by operating the device at higher temperature due to a reduced extrinsic base resistivity.

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“…The most commonly used metallization scheme for source/ drain contacts on these HEMTs is Ti/Al, with overlayers of Pt, Ni or Ti and then a layer of Au to reduce oxidation problems and lower the sheet resistance of the contact stack. [11][12][13][14][15][16][17][18][19][20][21][22][23] These contacts produce low specific contact resistances when annealed in the 750-900°C range but there are concerns about the long-term stability during high temperature operation, in part because if the metal layers begin to intermix, a low melting temperature AlAu 4 phase may form that can lead to contact shorting at small electrode separations. 19 One possible solution is to use a very high melting point diffusion barrier in place of the Pt, Ni or Ti in the contact stack.…”

Section: Introductionmentioning

confidence: 99%

Improved Long-Term Thermal Stability At 350°C Of TiB2–Based Ohmic Contacts On AlGaN/GaN High Electron Mobility Transistors

Khanna

Stafford

Pearton

et al. 2007

Journal of Elec Materi

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AlGaN/GaN High Electron Mobility Transistors (HEMTs) were fabricated with Ti/Al/TiB 2 /Ti/Au source/drain Ohmic contacts and a variety of gate metal schemes (Pt/Au, Ni/Au, Pt/TiB 2 /Au or Ni/TiB 2 /Au) and subjected to long-term annealing at 350°C. By comparison with companion devices with conventional Ti/Al/Pt/Au Ohmic contacts and Pt/Au gate contacts, the HEMTs with boridebased Ohmic metal and either Pt/Au, Ni/Au or Ni/TiB 2 /Au gate metal showed superior stability of both source-drain current and transconductance after 25 days aging at 350°C.

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An Al/sub 0.3/Ga/sub 0.7/N/GaN undoped channel heterostructure field effect transistor with F/sub max/ of 107 GHz

Cited by 73 publications

References 16 publications

Raman spectroscopy of GaN, AlGaN and AlN for process and growth monitoring/control

Raman spectroscopy of GaN, AlGaN and AlN for process and growth monitoring/control

Effect of Mg ionization efficiency on performance of Npn AlGaN/GaN heterojunction bipolar transistors

Improved Long-Term Thermal Stability At 350°C Of TiB2–Based Ohmic Contacts On AlGaN/GaN High Electron Mobility Transistors

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