Hot-electron energy relaxation time in AlGaN/GaN

Matulionis, A.; Liberis, J.; Ardaravičius, L.; Ramonas, M.; Matulionienė, I.; Smart, J.

doi:10.1088/0268-1242/17/3/101

Cited by 49 publications

(47 citation statements)

References 18 publications

(27 reference statements)

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“…The transition temperature is in a reasonably good agreement with the earlier experimental data: the LO phonons dominate at T e > 70 K when T 0 = 1.5 K [15], at T e > 160 K when T 0 = 80 K [16], and at T e > 300 K when T 0 = 293 K [6]. The Arrhenius-like dependence of the dissipated power on the inverse noise temperature (9) is valid at 80 K, while the modified expression (12) holds at room temperature.…”

Section: Discussionsupporting

confidence: 89%

“…When the electrons are displaced from equilibrium by the applied electric field, the electron temperature exceeds that of the lattice [5]. As a rule, the longitudinal noise temperature of hot electrons exceeds the electron temperature since additional sources of noise act in the bias direction; noise due to electron temperature fluctuations, inter-subband noise, real-space transfer noise, shot noise are several examples [5][6][7]. On the other hand, the transverse noise temperature approximately equals the electron temperature.…”

Section: Microwave Noise Techniquementioning

confidence: 99%

“…[6]. The noise temperature of hot electrons is measured at 10 GHz in the direction of bias, the bandwidth (∆f = 1 GHz) is mainly determined by the microwave amplifier.…”

Section: Microwave Noise Techniquementioning

confidence: 99%

“…The mismatch effect is taken into account as follows. Supposing that the sample is under bias and the calibrated noise generator is on, the noise power x ng detected by the radiometric set-up after the subtraction can be written as [6] …”

Section: Microwave Noise Techniquementioning

confidence: 99%

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Microwave noise technique for measurement of hot-electron energy relaxation time and hot-phonon lifetime

Šermukšnis¹

2007

Lithuanian J. Phys.

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Gated modulation-type radiometric technique for microwave noise measurement is upgraded for convenient investigation of hot-electron energy relaxation and hot-phonon dynamics in a channel with a high-density electron gas. The technique is applied to a GaN-based structure held at 80 and 293 K channel temperature. The results are discussed in terms of hot-phonon effect on hot-electron energy relaxation. The hot-phonon lifetime, estimated from the noise analysis, is compared with the values obtained by more traditional techniques.

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Section: Discussionsupporting

confidence: 89%

Section: Microwave Noise Techniquementioning

confidence: 99%

“…[6]. The noise temperature of hot electrons is measured at 10 GHz in the direction of bias, the bandwidth (∆f = 1 GHz) is mainly determined by the microwave amplifier.…”

Section: Microwave Noise Techniquementioning

confidence: 99%

Section: Microwave Noise Techniquementioning

confidence: 99%

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Microwave noise technique for measurement of hot-electron energy relaxation time and hot-phonon lifetime

Šermukšnis¹

2007

Lithuanian J. Phys.

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“…This high velocity arises in part from the high mobilities that have been observed in these heterostructures [12,13]. In contrast to this, however, there are both experiments and Monte Carlo simulations which suggest that a much lower value of the velocity occurs, of the order of 1×10 7 cm/s at fields above 10 kV/cm [14,15,16]. This same group has, however, obtained a drift velocity above 2×10 7 cm/s at around 140 kV/cm [17], with essentially linear behavior at lower fields, by using short pulses.…”

Section: Introductionmentioning

confidence: 99%

High field effects of GaN HEMTs.

Barker

Shul

2004

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This report represents the completion of a Laboratory-Directed Research and Development (LDRD) program to develop and fabricate geometric test structures for the measurement of transport properties in bulk GaN and AlGaN/GaN heterostructures. A large part of this study was spent examining fabrication issues related to the test structures used in these measurements, due to the fact that GaN processing is still in its infancy. One such issue had to do with surface passivation. Test samples without a surface passivation, often failed at electric fields below 50 kV/cm, due to surface breakdown. A silicon nitride passivation layer of approximately 200 nm was used to reduce the effects of surface states and premature surface breakdown. Another issue was finding quality contacts for the material, especially in the case of the AlGaN/GaN heterostructure samples. Poor contact performance in the heterostructures plagued the test structures with lower than expected velocities due to carrier injection from the contacts themselves. Using a titanium-rich ohmic contact reduced the contact resistance and stopped the carrier injection. The final test structures had an etch constriction with 3 varying lengths and widths (8×2, 10×3, 12x3, 12×4, 15×5, and 16×4 m) and massive contacts. A pulsed voltage input and a four-point measurement in a 50 Ω environment was used to determine the current through and the voltage dropped across the constriction. From these measurements, the drift velocity as a function of the applied electric field was calculated and thus, the velocity-field characteristics in n-type bulk GaN and AlGaN/GaN test structures were determined. These measurements show an apparent saturation velocity near to 2.5×10 7 cm/s at 180 kV/cm and 3.1×10 7 cm/s, at a field of 140 kV/cm, for the bulk GaN and AlGaN heterostructure samples, respectively.These experimental drift velocities mark the highest velocities measured in these materials to date and confirm the predictions of previous theoretical models using ensemble Monte Carlo simulations.

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Noise, Hot Carrier Effects

Matulionis¹

2007

Wiley Encyclopedia of Electrical and Electronics Engineering

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Hot-electron energy relaxation time in AlGaN/GaN

Cited by 49 publications

References 18 publications

Microwave noise technique for measurement of hot-electron energy relaxation time and hot-phonon lifetime

Microwave noise technique for measurement of hot-electron energy relaxation time and hot-phonon lifetime

High field effects of GaN HEMTs.

Noise, Hot Carrier Effects

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