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High‐Performance BeMgZnO/ZnO Heterostructure Field‐Effect Transistors
Author(s) -
Ding Kai,
Avrutin Vitaliy,
Izyumskaya Natalia,
Özgür Ümit,
Morkoç Hadis,
Šermukšnis Emilis,
Matulionis Arvydas
Publication year - 2020
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.202000371
Subject(s) - transconductance , cutoff frequency , materials science , heterojunction , optoelectronics , transistor , fabrication , saturation velocity , high electron mobility transistor , dielectric , field effect transistor , analytical chemistry (journal) , electrical engineering , chemistry , voltage , medicine , alternative medicine , pathology , chromatography , engineering
Herein, the growth and fabrication of BeMgZnO/ZnO heterostructure field‐effect transistors (HFETs) are reported on, as well as their direct current (DC) and radio frequency (RF) characterization. With a high 2D electron gas density of ≈8 × 10 12 cm −2 , made possible by BeO and MgO coalloying in the barrier, typical drain currents of 0.24 A mm −1 are obtained in Zn‐polar BeMgZnO/ZnO HFETs with a Be content of 2–3% and a Mg content below 30%. Typical on/off current ratios above 10 4 , transconductance values of ≈50 mS mm −1 , and current‐gain cutoff frequencies f T of 5.0 GHz, the highest among ZnO‐based FETs, are achieved in devices with a gate length of 1.5 μm using Al 2 O 3 as the gate dielectric. An average electron velocity above 1 × 10 7 cm s −1 , deduced from the bias‐dependent cutoff frequency and extraction of transit time under the gate, suggests that even with relatively long gate lengths the average electron velocity is near the theoretical limit (3.5 × 10 7 cm s −1 ) of the high peak velocity in ZnO.