High‐Performance BeMgZnO/ZnO Heterostructure Field‐Effect Transistors
Abstract
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 × 1012 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 104, transconductance values of ≈50 mS mm−1, and current‐gain cutoff frequencies fT of 5.0 GHz, the highest among ZnO‐based FETs, are achieved in devices with a gate length of 1.5 μm using Al2O3 as the gate dielectric. An average electron velocity above 1 × 107 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 × 107 cm s−1) of the high peak velocity in ZnO.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Oct 27, 2020
- Source ID
- 10.1002/pssr.202000371
Entities
People
- Arvydas Matulionis
- E. Šermukšnis
- Hadis H. Morkoç̌
- Kai Ding
- N. Izyumskaya
- Vitaliy Avrutin
- Ümit Özgür
Organizations
- Air Force Office of Scientific Research
- Virginia Commonwealth University