AlN Passivation Over AlGaN/GaN HFETs for Surface Heat Spreading

Tsurumi, Naohiro; Ueno, Hideki; Murata, Takuya; Ishida, Hideyuki; Uemoto, Yasuhiro; Ueda, T.; Inoue, Katsuro; Tanaka, Tsuyoshi

doi:10.1109/ted.2010.2044675

Cited by 62 publications

(30 citation statements)

References 8 publications

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“…Although the higher lattice-and thermalmismatches of Si generate a large number of dislocations and cracks, AlGaN/GaN HEMTs on Si have shown attractive device performance for high-power applications. 1,[4][5][6][9][10][11][12][13][14] Most high power switching devices require a high three terminal OFF-state breakdown voltage (BV gd ) with low specific on-resistance (R DS½ON ) values. To achieve high BV gd , researchers have tried increasing the buffer layer thicknesses, 1,4,5) using C-doped buffer GaN 11,12) or Fe-doped buffer GaN, 13) wide gate-drain spacing (L gd ), 2,10,11,15,16) incorporation of a field plate, 2,12) AlN passivation, 14) double heterostructure field-effect transistors, 6,16,17) and complete removal of the Si substrate.…”

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confidence: 99%

“…1,[4][5][6][9][10][11][12][13][14] Most high power switching devices require a high three terminal OFF-state breakdown voltage (BV gd ) with low specific on-resistance (R DS½ON ) values. To achieve high BV gd , researchers have tried increasing the buffer layer thicknesses, 1,4,5) using C-doped buffer GaN 11,12) or Fe-doped buffer GaN, 13) wide gate-drain spacing (L gd ), 2,10,11,15,16) incorporation of a field plate, 2,12) AlN passivation, 14) double heterostructure field-effect transistors, 6,16,17) and complete removal of the Si substrate. 18,19) The potential problem in increasing the buffer thickness (d Buff ) is the formation of large wafer bowing which is not good for the fabrication of devices using a conventional lithography process.…”

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Improved Power Device Figure-of-Merit ($4.0\times 10^{8}$ V$^{2}$ $\Omega^{-1}$ cm$^{-2}$) in AlGaN/GaN High-Electron-Mobility Transistors on High-Resistivity 4-in. Si

Arulkumaran

Vicknesh

et al. 2011

Appl. Phys. Express

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The OFF-state breakdown voltage (BV gd ) characteristics of AlGaN/GaN high-electron-mobility transistors (HEMTs) on a 4-in. Si substrate were investigated and analyzed. The HEMTs with L gd ¼ 10 m exhibited BV gd of 723 V with the specific on-resistance R DS½ON of 1.3 m cm 2 . Due to the improved ohmic contact, the devices exhibited low R DS½ON values. The power device figure-of-merit (FOM ¼ BV gd 2 =R DS½ON ) is as high as 4:0 Â 10 8 V 2 À1 cm À2 , the highest among the reported values for GaN HEMTs on a 4-in. Si. Due to the low vertical buffer leakage current, a high vertical breakdown voltage of $1200 V has been achieved with the total buffer thickness (d Buff ) of 2.2 m. # 2011 The Japan Society of Applied Physics I II-Nitride semiconductors are emerging as the best candidates for high-speed power switching devices. 1-7) Apart from AlGaN/GaN high-electron-mobility transistors (HEMTs) on SiC and sapphire, AlGaN/GaN HEMTs on Si substrate are emerging as the most suitable choice for commercialization due to their low cost and the availability of larger sizes even up to GaN on 6-in. Si 7) and 8-in. Si 8) substrates. Although the higher lattice-and thermalmismatches of Si generate a large number of dislocations and cracks, AlGaN/GaN HEMTs on Si have shown attractive device performance for high-power applications. 1,[4][5][6][9][10][11][12][13][14] Most high power switching devices require a high three terminal OFF-state breakdown voltage (BV gd ) with low specific on-resistance (R DS½ON ) values. To achieve high BV gd , researchers have tried increasing the buffer layer thicknesses, 1,4,5) using C-doped buffer GaN 11,12) or Fe-doped buffer GaN, 13) wide gate-drain spacing (L gd ), 2,10,11,15,16) incorporation of a field plate, 2,12) AlN passivation, 14) double heterostructure field-effect transistors, 6,16,17) and complete removal of the Si substrate. 18,19) The potential problem in increasing the buffer thickness (d Buff ) is the formation of large wafer bowing which is not good for the fabrication of devices using a conventional lithography process. Due to the double leakage path between the ohmic contact and the Si substrate, Visalli et al. realized that the field plate is limited to enhance the breakdown voltage at the L gd > 8 m. 17) To achieve a higher switching speed with a good power device figure-of-merit (FOM), the device structure should have a higher two-dimensional-electron gas (2DEG) mobility channel with low contact resistance (R c ). For high-power switching device applications, most research groups have used a conducting Si substrate for the fabrication of GaN HEMTs. Recently, we have demonstrated low R DS½ON with high FOM (¼ BV gd 2 =R DS½ON ¼ 2:0 Â 10 8 V 2 À1 cm À2 ) by implementing ohmic recess etching on AlGaN/GaN HEMTs on high-resistivity (HR)-Si (>10;000 cm) with a 1.2-nmthick AlN spacer layer. 15) Umeda et al. realized the boosting of BV gd in GaN HEMTs on an HR-Si substrate with channel stoppers. 20) In this study, we are reporting the improved OFF-state breakdown characteristics of AlGaN/...

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confidence: 99%

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confidence: 99%

Improved Power Device Figure-of-Merit ($4.0\times 10^{8}$ V$^{2}$ $\Omega^{-1}$ cm$^{-2}$) in AlGaN/GaN High-Electron-Mobility Transistors on High-Resistivity 4-in. Si

Arulkumaran

Vicknesh

et al. 2011

Appl. Phys. Express

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“…Direct liquid cooling was carried out by placing the GaN chip inside the heat-pipe structure, where ethanol was filled as a volatile working fluid as shown in fig.11 [7]. The thermal resistance was measured as function of pulse width that corresponds to the dissipated power as shown in fig.12.…”

Section: Direct Liquid Immersion Technologymentioning

confidence: 99%

Status Quo and trends of GaN power devices

Ueda

2013

2013 IEEE International Reliability Physics Symposium (IRPS)

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This paper reviews the recently developed technologies for GaN-based power devices which is coming close to the practical application. Experimentally fabricated GaN inverter system attained the world-highest conversion efficiency over 99.3% by using GIT (Gate Injection Transistor). Reliability issues become increasingly essential due to the increase of power density of GaN-based device. Passivation technique is addressed in view of improving the on-resistance as well as suppressing the current collapse. Direct liquid-immersion package is also demonstrated, where junction temperature is drastically reduced in the built-in heat pipe structure.

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“…Overcoming these issues by a novel device structure, we have demonstrated ultra high breakdown voltages of AlGaN/GaN HFETs using thick poly-crystalline AlN as a passivation film. The AlN gives high breakdown strength together with better heat dissipation suppressing the effect of the surface traps that would cause so-called current collapse [4]. Via-holes through sapphire at the drain electrodes enable very efficient layout of the lateral HFET array avoiding any undesired breakdown of passivation films.…”

Section: Power Switching Gan Transistorsmentioning

confidence: 99%

GaN Transistors for Power Switching and High Frequency Applications

Tsurumi

Uemoto

Sakai

et al. 2008

2008 IEEE Compound Semiconductor Integrated Circuits Symposium

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We review our state-of-the-art GaN-based device technologies for power switching at low frequencies and high frequency operation aiming at future millimeter-wave communication systems. These two applications are emerging in addition to the widely investigated power amplifiers at microwave frequencies for cellular base stations. As for the power switching GaN devices, we present a novel device structure called Gate Injection Transistors (GIT), which enables normally-off operation with high drain current. Here we also present the world highest breakdown voltage of 10400V in AlGaN/GaN HFETs. In the last part of this paper, we present GaN-based MIS-HFETs which exhibits as high f max as 203GHz. The successful integration of lowloss microstrip lines with via-holes onto sapphire enables compact 3-stage K-band amplifier MMIC of which a small-signal gain is as high as 22dB at 26GHz with a 3dB bandwidth of 25-29GHz. The presented devices are promising for the two emerging future applications demonstrating high enough potential of GaN-based transistors.

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AlN Passivation Over AlGaN/GaN HFETs for Surface Heat Spreading

Cited by 62 publications

References 8 publications

Improved Power Device Figure-of-Merit ($4.0\times 10^{8}$ V$^{2}$ $\Omega^{-1}$ cm$^{-2}$) in AlGaN/GaN High-Electron-Mobility Transistors on High-Resistivity 4-in. Si

Improved Power Device Figure-of-Merit ($4.0\times 10^{8}$ V$^{2}$ $\Omega^{-1}$ cm$^{-2}$) in AlGaN/GaN High-Electron-Mobility Transistors on High-Resistivity 4-in. Si

Status Quo and trends of GaN power devices

GaN Transistors for Power Switching and High Frequency Applications

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