Impact of post-deposition annealing on interfacial chemical bonding states between AlGaN and ZrO2 grown by atomic layer deposition

Abstract

The effect of post-deposition annealing on chemical bonding states at interface between Al 0.5 Ga 0.5 N and ZrO 2 grown by atomic layer deposition (ALD) is studied by angle-resolved x-ray photoelectron spectroscopy and high-resolution transmission electron microscopy. It has been found that both of Al-O/Al 2p and Ga-O/Ga 3d area ratio decrease at annealing temperatures lower than 500 C, which could be attributed to "clean up" effect of ALD-ZrO 2 on AlGaN. Compared to Ga spectra, a much larger decrease in Al-O/Al 2p ratio at a smaller take-off angle h is observed, which indicates higher effectiveness of the passivation of Al-O bond than Ga-O bond through "clean up" effect near the interface. However, degradation of ZrO 2 /AlGaN interface quality due to re-oxidation at higher annealing temperature (>500 C) is also found. The XPS spectra clearly reveal that Al atoms at ZrO 2 /AlGaN interface are easier to get oxidized as compared with Ga atoms. V C 2015 AIP Publishing LLC. [http://dx.

Effect of surface pretreatment on interfacial chemical bonding states of atomic layer deposited ZrO2 on AlGaN

“…Such upward band bending could be ascribe to the surface Fermi-level pinning caused by interfacial oxide related defects, which is consistent with our earlier observations. 8,20,23 In order to distinguish the difference on the roles between Ga and Al atoms during parasitic oxidation and facilitate the This could be attributed to that Al atoms, which have a higher reactivity, [24][25][26][27] are easier to be oxidized than Ga atoms at AlGaN surface during ALD process. In fact, the formation of the interfacial oxide layer for BOE treated AlGaN during the ALD can also be further confirmed by HR-TEM shown in Fig.…”

Band alignment between 4H-SiC and atomic-layer-deposited ZrO2determined by X-ray photoelectron spectroscopy

“…However, compared to the peak area ratio of the Si-O bond to Si 2p for the bulk 4H-SiC substrate, an obviously smaller ratio is observed for the ZrO 2 =SiC sample, which implies that the parasitic oxidation layer formed during ALD could be extremely thin. [18][19][20] As can be seen from Fig. 4, the Si 2p 3=2 and Zr 3d 5=2 spectra at ZrO 2 =SiC interface show peaks at 101.44 and 182.89 eV, respectively.…”

Band alignment of HfO2/AlN heterojunction investigated by X-ray photoelectron spectroscopy

“…The existence of oxygen related chemical bonding states of Al 2p spectrum could be attributed to the parasitic oxidation of AlN surface after cleaning during ALD process. 17,18 It is obvious from Fig. 1(a) that the Al-N bond of Al 2p spectrum shows a trend to shift to lower binding energies with the decrease of h, which indicates a strong upward band bending occurred at AlN surface.…”