Effects of Working Pressure on the Structure and Electrical Properties of AlScN Thin Films

doi:10.15541/jim20250344

Abstract

Abstract:

Since ferroelectric properties of Al_1-_xSc_xN thin films were experimentally confirmed in 2019, wurtzite-structured ferroelectric materials have received worldwide attention. However, the strong dependence of their ferroelectric performance on deposition parameters still remains a significant challenge, limiting their reliable integration into practical device applications. This study aims to systematically investigate the influence of sputtering working pressure on microstructural evolution and resultant ferroelectric properties of Al_1-_xSc_xN thin films. The primary goal is to identify the optimal pressure window that yields superior ferroelectric performance and to understand the underlying structure-property relationships. Al_0.71Sc_0.29N thin films were deposited on silicon substrates using reactive magnetron sputtering in a pure nitrogen atmosphere, and experienced the working pressure varied from 0.27 Pa to 1.33 Pa. The correlation between crystal structure, surface morphology, and ferroelectric properties of the thin film was analyzed. The results showed that the working pressure significantly affected crystallization quality of Al_0.71Sc_0.29N thin films, among which prepared under 0.52 Pa had the best crystallization quality and excellent ferroelectric properties. As the working pressure increased, the pyramid-like structures began to appear on surface of the film and gradually increased, while the static leakage current also gradually decreased. This work conclusively demonstrates that sputtering working pressure is one of the decisive factors in tuning microstructure and ferroelectricity of Al_1-_xSc_xN films. The correlation between working pressure-induced morphological changes and leakage current suppression offers valuable insights for engineering high-performance wurtzite ferroelectric devices.

Key words: AlScN film, working pressure, micro structure, ferroelectric property

CLC Number:

TQ174

SUI Jinyang, ZHOU Dayu, ZHAO Wenjin, TONG Yi, WANG Xinpeng. Effects of Working Pressure on the Structure and Electrical Properties of AlScN Thin Films[J]. Journal of Inorganic Materials, 2026, 41(4): 486-492.

Figures/Tables 7

Fig. 1 XPS spectra of Al0.71Sc0.29N films deposited at different working pressures (a-c) Al2p; (d-f) Sc2p and N1s

Table 1 Atomic percentages of elements for Al0.71Sc0.29N films prepared at different working pressures

Working pressure/Pa	Al/%	Sc/%	N/%	O/%
0.27	29.64	13.33	43.12	13.39
0.52	31.58	12.59	40.79	15.05
0.93	30.42	12.60	34.56	22.42

Fig. 2 XRD patterns, deposition rates and lattice parameters of Al0.71Sc0.29N films deposited at different working pressures (a) XRD patterns; (b) Deposition rate, intensity and full width at half maximum (FWHM) of the (0002) diffraction peak; (c) GIXRD patterns; (d) Calculated lattice parameters c, a and c/a

Fig. 3 Surface morphologies of Al0.71Sc0.29N films (a) Samples deposited at different working pressures (×100 k); (b) Sample deposited at 0.93 Pa (×200 k)

Fig. 4 P-E and I-E curves for Al0.71Sc0.29N films deposited at different working pressures

Fig. 5 I-t curve fitting (a), coercive electric field and remanent polarization (b) of Al0.71Sc0.29N films deposited at different working pressures Colorful figures are available on website

Fig. 6 Static J-E curves (a) and current density at different electric fields (b) of Al0.71Sc0.29N films deposited at different working pressures

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