High‐Temperature Operation of AlxGa1−xN (x > 0.4) Channel Metal Oxide Semiconductor Heterostructure Field Effect Transistors with High‐k Atomic Layer Deposited Gate Oxides. Issue 7 (7th February 2020)

• Record Type: Journal Article
• Authors: Mollah, Shahab; Hussain, Kamal; Floyd, Richard; Mamun, Abdullah; Gaevski, Mikhail; Chandrashekhar, MVS; Ahmad, Iftikhar; Simin, Grigory; Wheeler, Virginia; Eddy, Charles; Khan, Asif
• Other Names: Shahedipour-Sandvik F. Shadi guestEditor.; Qhalid Fareed guestEditor.
• Is Part Of: Physica status solidi. Volume 217:Issue 7(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-02-07
• Subjects: Al0.65Ga0.35N/Al0.4Ga0.6N metal oxide semiconductor heterostructure field effect transistors -- high-k atomic layer-deposited oxides -- high temperatures -- temperature-dependent mobilities -- threshold voltages; Solid state physics -- Periodicals; Solids -- Industrial applications -- Periodicals; 530.41
• DOI: 10.1002/pssa.201900802
• Languages: English
• ISSNs: 1862-6300

Abstract

Abstract : Due to their superior breakdown fields compared with GaN and SiC and high thermal conductivity, Al x Ga1− x N ( x > 0.4) channel high‐electron‐mobility transistors (HEMTs) will find applications in extreme environments such as power electronics. Herein, the high‐temperature operation of ultrawide‐bandgap (UWBG) Al0.65 Ga0.35 N/Al0.4 Ga0.6 N metal oxide semiconductor heterostructure field effect transistors (MOSHFETs) with atomic layer‐deposited (ALD) high‐ k gate dielectrics TiO2, Al2 O3, and ZrO2 is reported. As compared with similar geometry HFETs, these devices exhibit a simultaneous reduction in gate‐leakage current by ≈10 4 and a positive shift of the threshold voltage as much as 4 V. This positive threshold shift indicates the introduction of negative charges at the oxide/barrier interface and within the thin oxide, attributed to the pre‐ALD plasma treatment. The gate leakage increases weakly with temperature up to 250 °C, whereas the peak drain currents decrease from ≈0.5 to 0.3 A mm −1 . An analysis of the C – V and I – V characteristics reveals that this drain current decrease is due to a reduction in channel electron mobility. The potential mechanisms responsible for this are discussed. Up to the measured temperature of 250 °C, the devices withstand repeated temperature cycles without catastrophic degradation or breakdown, underscoring the promise of these materials. Abstract : A systematic study of the high‐temperature operation of ultrawide‐bandgap (UWBG) Al0.65 Ga0.35 N/Al0.4 Ga0.6 N metal oxide semiconductor heterostructure field effect transistors (MOSHFETs) with atomic layer‐deposited (ALD) high‐ k gate dielectrics TiO2, Al2 O3, and ZrO2 is presented. A simultaneous gate leakage reduction with a positive shift in the threshold voltage is discussed. In addition, gate and drain current dependencies on temperature are presented.