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Department of Physics

Staff profile

Publication details for Prof Richard Abram

Herbert, D C, Uren, M J, Hughes, B T, Hayes, D G, Birbeck, J C H, Balmer, R, Martin, T, Crow, G C, Abram, R A, Walmsley, M, Davies, R A, Wallis, R H, Phillips, W A & Jones, S (2002). Monte Carlo simulations of AlGaN/GaN heterojunction field-effect transistors (HFETs). Journal of Physics: Condensed Matter 14(13): 3479-3497.

Author(s) from Durham


Self-consistent Monte Carlo simulations are reported for AlGaN/GaN HFETs. Hot-carrier scattering rates are determined by fitting experimental ionization coefficients and the doping character of the GaN is obtained from substrate bias measurements. Preliminary simulations for a simple model of the AlGaN surface are described and results are found to be consistent with experimental data. The high-frequency response of short-gate-length transistors is found to be sensitive to the charge state of the free AlGaN surface and it is proposed that current-slump phenomena may also be related to deep levels at this surface. Breakdown calculations show interesting two-dimensional effects close to the drain contact.



Mishra U K and Zolper J C (ed) 2001 IEEE Trans. Electron Devices 2001 48 (Special Issue on group III–N
semiconductor electronics)


Ohno Y and Kuzuhara M 2001 Applications of GaN-based heterojunction FETS for advanced wireless
communication IEEE Trans. Electron Devices 48 517–24


Uren M J, Herbert D C, Martin T, Hughes B T, Birbeck J, Balmer R and Jones S K 2001 Back bias effects in
AlGaN/GaN HFETs Proc. 4th Int. Conf. on Nitride Semiconductors; Phys. Status Solidi at press


Kunihiro K, Kasahara K, TakahashiYand OhnoY1999 Experimental evaluation of impact ionisation coefficient
in GaN IEEE Electron Device Lett. 20 608–10.


Wraback M, Shen H, Carrano J C, Li T, Campbell J C, Schurman M J and Ferguson I T 2000 Time resolved
electroabsorption measurement of the electron velocity–field characteristics in GaN Appl. Phys. Lett. 76


Farahmand M, Garetto C, Bellotti E, Brennan K F, Goano M, Ghillino E, Ghione G, Albrecht J D and Ruden P P
2001 Monte Carlo simulation of electron transport in the III-nitride wurtzite phase materials system: binaries
and ternaries IEEE Trans. Electron Devices 48 535–42


Kolnik J, Oguzman I H, Brennan K F, Wang R, Ruden P and Wang Y 1995 Electronic transport studies of bulk
zincblende and wurtzite phases of GaN based on ensemble Monte Carlo calculation including a full zone
band structure J. Appl. Phys. 78 1033–8


Littlejohn M A, Hauser J R and Glisson T H 1975 Monte Carlo calculation of the velocity–field relationship for
gallium nitride Appl. Phys. Lett. 26 625–7


Sun C K, Huang Y L, Keller S, Mishra U K and Denbaars S P 1999 Ultrafast electron dynamics study of GaN
Phys. Rev. B 59 13 535–8


Foutz B E, Oleary S K, Shur M S and Eastman L F 1999 Transient electron transport in wurtzite GaN, InN and
AlN J. Appl. Phys. 85 7727–34


Ambacher O et al 1999 Two-dimensional electron gases induced by spontaneous and piezoelectric polarisation
charges in N- and Ga-face AlGaN heterostructures J. Appl. Phys. 85 3222–33


Vetury R, ZhangNQ,Keller S and MishraUK2001 The impact of surface states on the dc and RF characteristics
of AlGaN/GaN HFETs IEEE Trans. Electron Devices 48 560–6


Tan C H, David J P R, Rees G J, Tozer R C and Herbert D C 2001 Treatment of soft threshold in impact ionisation
J. Appl. Phys. at press


Wu Y F, Keller B P, Keller S, Kapolnek D, Kozody P, Denbaars S P and Mishra U K 1996 Very high breakdown
voltage and large transconductance realised on GaN heterojunction field effect transistors Appl. Phys. Lett.
69 1438–40


Herbert D C1993 Breakdown voltage in ultra-thin p–i–n diodes Semicond. Sci. Technol. 8 1993–8


Crow G C and Abram R A 2001 The transient signal response of submicron vertical silicon field effect transistors
Semicond. Sci. Technol. 16 250–4


Davies R A, Bazely D J, Jones S K, Lovekin H A, PhillipsWA,Wallis R H, Birbeck J C, Martin T and UrenMJ
2000 The gate-length dependent performance of AlGaN/GaN HFETs with silicon nitride passivation EDMO-
2000: IEEE Symp. on High Performance Electron Devices for Microwave and Opto-Electronic Applications.