Temperature-dependent Lowering of Coercive Field in 300 nm Sputtered Ferroelectric Al_0.70Sc_0.30N

Abstract

This paper reports the temperature-dependent ferroelectric properties of sputtered ferroelectric Al0.70Sc0.30N. The coercive field is experimentally demonstrated to decrease by 1.5 MV/cm in 300 nm films in the temperature range of 20- 193 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sup> C, corresponding to an average linear coefficient of decrease of 8.8 kV/ <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sup> C. In the same range, the remnant polarization varies by 23.5% between 90-114 μC/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> without a significant drop-off at higher temperatures. Thermally cycling the chip between room temperature and the highest achievable temperature of 193 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sup> C shows a reversible tuning of the coercive field, paving the path towards on-chip ovenization-based control of ferroelectric properties. The dielectric breakdown under AC and DC testing are driven by filamentary and thermally driven breakdown processes respectively. These breakdown processes suggest the potential for high frequency operation of sputtered Al0.70Sc0.30N as a ferroelectric thin film at elevated temperatures with low leakage.