Low-frequency noise in AlTiO/AlGaN/GaN metal-insulator-semiconductor heterojunction field-effect transistors

Abstract

Using aluminum titanium oxide (AlTiO, an alloy of Al2O3 and TiO2) as a high-k gate insulator, we fabricated and investigated AlTiO/AlGaN/GaN metal-insulator-semiconductor heterojunction field-effect transistors. From current low-frequency noise (LFN) characterization, we find Lorentzian spectra near the threshold voltage, in addition to 1/f spectra for the well-above-threshold regime. The Lorentzian spectra are attributed to electron trapping/detrapping with two specific time constants, ∼25 ms and ∼3 ms, which are independent of the gate length and the gate voltage, corresponding to two trap level depths of 0.5–0.7 eV with a 0.06 eV difference in the AlTiO insulator. In addition, gate leakage currents are analyzed and attributed to the Poole-Frenkel mechanism due to traps in the AlTiO insulator, where the extracted trap level depth is consistent with the Lorentzian LFN.

Current linearity and operation stability in Al2O3-gate AlGaN/GaN MOS high electron mobility transistors

“…For the GaN-based MIS-HEMTs using Al 2 O 3 , SiN x and AlTiO, it has been reported that the Poole-Frenkel (PF) emission conduction was dominant for gate leakage current. [45][46][47][48] Similarly to the V TH recovery behavior, there is a possibility the reduction of leakage current arises from decrease in defect levels in the Al 2 O 3 layer, contributing to the suppression of the PF hopping conduction.…”

Improved operation stability of Al2O3/AlGaN/GaN MOS high-electron-mobility transistors grown on GaN substrates

“…For the GaN-based MIS HEMTs using Al 2 O 3 , SiN x and AlTiO, it has been reported that the Poole-Frenkel (PF) emission conduction was dominant for gate leakage current. [22][23][24][25] In the same way as the V TH recovery, decrease in defect levels in the Al 2 O 3 layer is responsible for the reduction of leakage current, contributing to the suppression of the PF hopping conduction.…”

Synthesis and characterization of mist chemical vapor deposited aluminum titanium oxide films

“…As a matter of fact, a high-quality Al 1-x Ti x O y gate insulator deposited by the atomic layer deposition (ALD) method and other vacuum deposition techniques has been used for Si-based, [3][4][5] GaAs-based 6,7) and GaN-based devices. 8,9) One alternative approach to obtain Al 1-x Ti x O y thin films is the mist chemical vapor deposition (mist-CVD) technique, which can deposit various metal-oxide thin films from relative non-toxic and nonpyrophoric aqueous solution under atmospheric pressure. As such, mist-CVD is regarded as relatively simple, safe and cost-effective.…”