[PDF]    http://dx.doi.org/10.3952/lithjphys.47417

Open access article / Atviros prieigos straipsnis

Lith. J. Phys. 47, 63–67 (2007)


RELAXATION OF CONDUCTIVITY IN AlGaN/AlN/GaN TWO-DIMENSIONAL ELECTRON GAS AT HIGH ELECTRIC FIELDS*
L. Ardaravičius, O. Kiprijanovič, and J. Liberis
Semiconductor Physics Institute, A. Goštauto 11, LT-01108 Vilnius, Lithuania
E-mail: linas@pfi.lt

Received 28 September 2007; revised 5 November 2007; accepted 21 November 2007

AlGaN/AlN/GaN heterostucture with a very thin (0.6 nm) AlN spacer was investigated by conductivity relaxation measurements after a strong electric field action. To obtain the two-dimensional electron gas (2DEG) channel transport properties at high electric fields the relaxation results were extrapolated to the time of the peak of an applied nanosecond high-voltage electric pulse. Significant decrease of hot electron sheet density at high electric fields was revealed. The measured sample conductivity relaxation is decided not only by the changes of 2DEG channel conductivity due to variation of sheet density. This does not allow one to obtain corrected drift velocity values at high electric fields. The obtained results show that the AlN thickness must be more than 0.6 nm.
Keywords: nitride heterostructures, two-dimensional electron gas, hot electrons, AlGaN/AlN/GaN
PACS: 72.20.Jv, 73.40.Kp, 73.50.Fq
*The report presented at the 37th Lithuanian National Physics Conference, 11–13 June 2007, Vilnius, Lithuania.


AlGaN/AlN/GaN DVIMAČIŲ ELEKTRONŲ DUJŲ LAIDUMO RELAKSACIJA STIPRIUOSE ELEKTRINIUOSE LAUKUOSE
L. Ardaravičius, O. Kiprijanovič, J. Liberis
Puslaidininkių fizikos institutas, Vilnius, Lietuva

AlGaN/AlN/GaN įvairialytis darinys, turintis labai ploną (0,6 nm) AlN tarpinį sluoksnį, buvo tirtas matuojant laidumo relaksaciją po stipraus elektrinio lauko impulso. Norint įvertinti dvimačių elektroninių dujų kanalo pernašos savybes, relaksacijos matavimo rezultatai buvo ekstrapoliuoti į lauko maksimumo momentą, kai buvo paleistas nanosekundinės trukmės aukštos įtampos elektrinis impulsas. Pastebėtas žymus karštųjų elektronų dvimačių elektronų dujų tankio sumažėjimas stipriame elektriniame lauke. Išmatuota bandinio laidumo relaksacija, vykstanti išjungus stiprų elektrinį lauką, nėra lemiama vien dvimačio kanalo laidumo kitimo, kintant jame elektronų tankiui. Iš šio laidumo kitimo negalime vertinti dvimačių elektroninių dujų tankio ir tokiu būdu patikslinti dreifo greičio stipriame elektriniame lauke. Siekiant pagerinti kanalo savybes, sluoksnio storis turi būti didesnis nei 0,6 nm.


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