Large periphery high-power AlGaN/GaN metal-oxide-semiconductor heterostructure field effect transistors on SiC with oxide-bridging

Applied Physics Letters

et al. 2001

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251

134

We report on a metal–insulator–semiconductor heterostructure field-effect transistor (MISHFET) using Si3N4 film simultaneously for channel passivation and as a gate insulator. This design results in increased radio-frequency (rf) powers by reduction of the current collapse and it reduces the gate leakage currents by four orders of magnitude. A MISHFET room temperature gate current of about 90 pA/mm increases to only 1000 pA/mm at ambient temperature as high as 300 °C. Pulsed measurements show that unlike metal–oxide–semiconductor HFETs and regular HFETs, in a Si3N4 MISHFET, the gate voltage amplitude required for current collapse is much higher than the threshold voltage. Therefore, it exhibits significantly reduced rf current collapse.

mentioning

confidence: 83%

“…1 was grown on a sapphire substrate using low-pressure metalorganic chemical vapor deposition ͑MOCVD͒. A device fabrication procedure similar to that reported earlier [7][8][9] was then used. Three sets of devices with identical geometry ͑gate length 1 m, source-drain opening 5 m, gate width 100 m͒ were fabricated on the same wafer.…”

mentioning

confidence: 99%

Si 3 N 4 / AlGaN/GaN –metal–insulator–semiconductor heterostructure field–effect transistors

Koudymov

Applied Physics Letters

et al. 2001

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251

134

“…Furthermore, a maximum current of more than 5 A from a single-multigate on-wafer MOSH-FET was also measured and reported recently. 3 These extremely high channel currents in conjunction with breakdown voltages above 100 V, suggest the possibility of obtaining record high microwave output powers in GaNAlGaN field-effect transistors ͑FETs͒. A maximum rf output power in a class-A amplifier mode should be about ͑ 1.3A/mm͒100V/8ϭ16.25 w/mm for MOSHFETs and about ͑ 0.7A/mm͒100V/8ϭ8.75 w/mm for HFETs.…”

Section: Mechanism Of Radio-frequency Current Collapse In Gan-algan Fmentioning

confidence: 99%

“…͑i͒ Since the gate leakage current in MOSHFETs is about 4-6 orders less than that in HFETs, 3 the gate leakage current as the mechanism responsible for current collapse can be ruled out. Also, since the surface conditions are quite different for HFETs and MOSHFETs, we believe that surface states in the source-gate-drain openings do not contribute significantly to the current collapse.…”

Section: Mechanism Of Radio-frequency Current Collapse In Gan-algan Fmentioning

confidence: 99%

Mechanism of radio-frequency current collapse in GaN–AlGaN field-effect transistors

Tarakji

Applied Physics Letters

Il’inskaya

et al. 2001

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The mechanism of radio-frequency current collapse in GaN–AlGaN heterojunction field-effect transistors (HFETs) was investigated using a comparative study of HFET and metal–oxide–semiconductor HFET current–voltage (I–V) and transfer characteristics under dc and short-pulsed voltage biasing. Significant current collapse occurs when the gate voltage is pulsed, whereas under drain pulsing the I–V curves are close to those in steady-state conditions. Contrary to previous reports, we conclude that the transverse electric field across the wide-band-gap barrier layer separating the gate and the channel rather than the gate or surface leakage currents or high-field effects in the gate–drain spacing is responsible for the current collapse. We find that the microwave power degradation in GaN–AlGaN HFETs can be explained by the difference between dc and pulsed I–V characteristics.

“…For this study, the MOSHFET devices fabricated and reported earlier [10] were used. The devices with the gate length of 1 m were fabricated over insulating SiC substrates.…”

Section: Moshfet Rf Switch Characteristicsmentioning

confidence: 99%

Low-loss high power RF switching using multifinger AlGaN/GaN MOSHFETs

Koudymov

IEEE Electron Device Lett.

et al. 2002

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Abstract-We demonstrate a novel RF switch based on a multifinger AlGaN/GaN MOSHFET. Record high saturation current and breakdown voltage, extremely low gate leakage current and low gate capacitance of the III-N MOSHFETs make them excellent active elements for RF switching. Using a single element test circuit with 1-mm wide multifinger MOSHFET we achieved 0.27 dB insertion loss and more than 40 dB isolation. These parameters can be further improved by impedance matching and by using submicron gate devices. The maximum switching power extrapolated from the results for 1A/mm 100 m wide device exceeds 40 W for a 1-mm wide 2-A/mm MOSHFET.Index Terms-Field-effect transistor (FET), GaN, HEMT, heterostructure field-effect transistor (HFET), MOSHFET, RF, switch, wireless.