Lithuanian Journal of Physics article / Lietuvos fizikos žurnalo straipsnis

ELECTRON TRANSPORT IN A COUPLED GaN/AlN/GaN CHANNEL Of NITRIDE HFET
Linas Ardaravičius, Oleg Kiprijanovič, and Juozapas Liberis
Center for Physical Sciences and Technology, Saulėtekio 3, LT-10257 Vilnius, Lithuania
E-mail: linas.ardaravicius@ftmc.lt

Received 1 June 2016; revised 30 July 2016; accepted 23 September 2016

Longitudinal hot-electron transport is investigated for the alloy-free AlGaN/AlN/{GaN/AlN/GaN} heterostructure at electric fields up to 380 kV/cm. The structure featured a coupled channel with a camelback electron density profile. The hot-electron drift velocity in the coupled channel is estimated as ~1.5×10⁷ cm/s and is ~50% higher as compared with the standard AlN-spacer GaN 2DEG channel. The HFET with the pristine 2DEG density of 1.75×10¹³ cm^–2 confined in the coupled channel demonstrates the optimal frequency performance in terms of electron velocity at a relatively low gate bias of V_GS = –1.75 V. These results are consistent with the ultra-fast decay of hot phonons.

Keywords: nitride heterostructure, HFET, electron drift velocity, hot phonons, high electric fields
PACS: 72.10.Di, 72.20.Ht, 72.20.Fr, 72.30.+q, 85.30.Tv

ELEKTRONŲ PERNAŠA NITRIDINIAM LAUKO TRANZISTORIUI SKIRTAME SUSIETAME GaN/AlN/GaN KANALE

Linas Ardaravičius, Oleg Kiprijanovič, Juozapas Liberis
Fizinių ir technologijos mokslų centras, Vilnius, Lietuva

Eksperimentiškai ištirti su kvazidvimatėmis elektronų dujomis {GaN/AlN/GaN} susieti kanalai. Tirtas kanalas suformuotas AlGaN/AlN/GaN/AlN/GaN įvairialyčiame darinyje, užaugintame MOCVD būdu ant safyro padėklo. Dvimatės elektronų dujos buvo veikiamos išoriniu elektriniu lauku, nukreiptu lygiagrečiai darinio plokštumai (statmenai c ašiai). Nanosekundinė VACH matavimo technika panaudota siekiant sumažinti Džaulio šilumos įtaką. Elektronų dreifo greitis įvertintas darant prielaidą, kad elektronų tankis nuo elektrinio lauko nepriklauso. Nustatyta, kad susietame {GaN/AlN/GaN} kanale didžiausias elektronų dreifo greitis yra 1,5×10⁷ cm/s, kai elektrinio lauko stipris – 130 kV/cm, o tai 50 % viršija dreifo greitį standartiniame GaN dvimačių elektronų dujų kanale, nuo barjero atskirtame tarpiniu AlN sluoksniu. Parodyta, kad susieto nitridų kanalo lauko tranzistorius pasižymi geriausia dažnine charakteristika, kai sklendės įtampa gana maža. Maksimalus dreifo greitis ir optimali tranzistoriaus veika susietame kanale priklauso nuo ultraspartaus karštųjų optinių fononų suirimo.

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