Electrical properties and interface abruptness of AlSiO gate dielectric grown on 0001¯ N-polar and (0001) Ga-polar GaN

Abstract

The electrical properties and the interface abruptness of aluminum silicon oxide (AlSiO) dielectric grown in situ on 0001¯ N-polar and (0001) Ga-polar GaN by metal organic chemical vapor deposition were studied by means of capacitance-voltage (CV) and atom probe tomography (APT) measurements. The growth of AlSiO on N-polar GaN resulted in a positive flatband voltage shift of 2.27 V with respect to that on Ga-polar GaN, which exemplifies the influence of the GaN surface polarization charge on the electrical properties of GaN-based metal oxide semiconductor (MOS) devices. The AlSiO/GaN(N-polar) interface was sharp, which resulted in nondispersive CV characteristics and a relatively low density of interface states (Dit) of 1.48 × 1012 cm−2. An intermixed layer of AlGaSiO was present at the interface between AlSiO and Ga-polar GaN, which contributed to the measured dispersive CV characteristics and resulted in an ∼2× higher Dit than that on N-polar GaN. The superior properties of the N-polar AlSiO MOS devices are promising for further advancement of N-polar GaN-based high electron mobility transistors for high-frequency and power electronics applications.

Synthesis of Al Thin Films with High Optical Transmittance by DC Magnetron Sputtering Process Parameter Optimization

“…4 with the increase of working gas pressure, which is quite opposite to the sputtering current increasing trend. The relationship between sputtering voltage (V) and current (I) at a constant sputtering power (P) with the variation of working gas pressure can be calculated using (2).…”

Improved operational reliability of MOCVD-grown AlSiO gate dielectric on β-Ga2O3 (001) by post-metallization annealing

“…Aluminum silicon oxide (AlSiO) has been proposed as a high-quality and reliable gate dielectric for GaN-based devices [17][18][19]. Alloying of Al 2 O 3 with silicon to form amorphous AlSiO has the potential to incorporate the advantages of both SiO 2 (E g = 9.0 eV) and Al 2 O 3 (E g = 6.7 eV) thus realizing high band offsets and high breakdown strength [18,20]. A low interface states (D it ) of ∼10 12 cm −2 eV −1 was achieved in AlSiO on Ga-polar GaN using metal-organic chemical vapor deposition (MOCVD) technique and a dielectric lifetime of 20 years for electric fields higher than 3 MV cm −1 was predicted by Chan et al [17,21].…”

“…A low interface states (D it ) of ∼10 12 cm −2 eV −1 was achieved in AlSiO on Ga-polar GaN using metal-organic chemical vapor deposition (MOCVD) technique and a dielectric lifetime of 20 years for electric fields higher than 3 MV cm −1 was predicted by Chan et al [17,21]. Sayed et al studied the impact of GaN polarity and the effect of post-metallization annealing (PMA) on the electrical properties of AlSiO/Npolar GaN MOS devices [20,22,23]. Annealing in air ambient at 370 • C was reported to reduce the density of near-interface traps by a factor of two from 5.6 × 10 11 to 2.6 × 10 11 cm −2 [23].…”

Characterization of AlSiO dielectrics with varying silicon composition for N-polar GaN-based devices

“…Kikuta et al and our group demonstrated that the post-deposition annealing of PEALD-deposited AlSiO and the post-metallization annealing of MOCVD-grown AlSiO, respectively, can further improve the bulk and interfacial properties of AlSiO resulting in improved operation stability [16,17]. Recently, we showed that the GaN polarity can impact the electrical and interfacial properties of AlSiO metal oxide semiconductor (MOS) devices by demonstrating that the growth of AlSiO (with a silicon composition of 7%) on Npolar GaN resulted in a positive flat-band shift and sharper interface with respect to AlSiO grown on Ga-polar GaN [18]. The exceptional performance of GaN transistors based on the N-polar technology for high-frequency and voltage-switching applications [19][20][21] motivated this investigation towards the understanding of the role of the silicon composition in AlSiO for future use in the gate stack of next-generation N-polar GaN-based transistors.…”