Infrared-laser based characterization of the pyroelectricity in AlScN thin-films

Bette, Sebastian; Fichtner, Simon; Bröker, Sebastian; Nielen, Lutz; Schmitz-Kempen, Thorsten; Wagner, Bernhard; Buggenhout, Carl Van; Tiedke, S.; Tappertzhofen, Stefan

doi:10.1016/j.tsf.2019.137623

Cited by 12 publications

(3 citation statements)

References 28 publications

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“…Although in general pyroelectric coefficients of ScAlN increases with increasing Sc doping concentration, this value might vary across films prepared by different deposition methods due to film and substrate properties, and impurity levels in the films . The pyroelectric coefficient of our 20% ScAlN pyroelectric detectors show ∼11.4 μC/m 2 K at room temperature, slightly higher than those reported in the literature of ∼20% Sc-doped AlN. , Kurz et al reported a pyroelectric coefficient of ∼8 μC/m 2 K at room temperature for 22% Sc-doped AlN and Bette et al reported pyroelectric coefficient ∼9.7 μC/m 2 K for 27% Sc-doped AlN.…”

Section: Resultscontrasting

confidence: 55%

“… 44 The pyroelectric coefficient of our 20% ScAlN pyroelectric detectors show ∼11.4 μC/m 2 K at room temperature, slightly higher than those reported in the literature of ∼20% Sc-doped AlN. 44 , 47 Kurz et al 44 reported a pyroelectric coefficient of ∼8 μC/m 2 K at room temperature for 22% Sc-doped AlN and Bette et al 47 reported pyroelectric coefficient ∼9.7 μC/m 2 K for 27% Sc-doped AlN.…”

Section: Resultsmentioning

confidence: 49%

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Miniaturized CO₂ Gas Sensor Using 20% ScAlN-Based Pyroelectric Detector

Liang

Chen

et al. 2022

ACS Sens.

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NDIR CO 2 gas sensors using a 10-cm-long gas channel and CMOS-compatible 12% doped ScAlN pyroelectric detector have previously demonstrated detection limits down to 25 ppm and fast response time of ∼2 s. Here, we increase the doping concentration of Sc to 20% in our ScAlN-based pyroelectric detector and miniaturize the gas channel by ∼65× volume with length reduction from 10 to 4 cm and diameter reduction from 5 to 1 mm. The CMOS-compatible 20% ScAlN-based pyroelectric detectors are fabricated over 8-in. wafers, allowing cost reduction leveraging on semiconductor manufacturing. Cross-sectional TEM images show the presence of abnormally oriented grains in the 20% ScAlN sensing layer in the pyroelectric detector stack. Optically, the absorption spectrum of the pyroelectric detector stack across the mid-infrared wavelength region shows ∼50% absorption at the CO 2 absorption wavelength of 4.26 μm. The pyroelectric coefficient of these 20% ScAlN with abnormally oriented grains shows, in general, a higher value compared to that for 12% ScAlN. While keeping the temperature variation constant at 2 °C, we note that the pyroelectric coefficient seems to increase with background temperature. CO 2 gas responses are measured for 20% ScAlN-based pyroelectric detectors in both 10-cm-long and 4-cm-long gas channels, respectively. The results show that for the miniaturized CO 2 gas sensor, we are able to measure the gas response from 5000 ppm down to 100 ppm of CO 2 gas concentration with CO 2 gas response time of ∼5 s, sufficient for practical applications as the average outdoor CO 2 level is ∼400 ppm. The selectivity of this miniaturized CO 2 gas sensor is also tested by mixing CO 2 with nitrogen and 49% sulfur hexafluoride, respectively. The results show high selectivity to CO 2 with nitrogen and 49% sulfur hexafluoride each causing a minimum ∼0.39% and ∼0.36% signal voltage change, respectively. These results bring promise to compact and miniature low cost CO 2 gas sensors based on pyroelectric detectors, which could possibly be integrated with consumer electronics for real-time air quality monitoring.

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Section: Resultscontrasting

confidence: 55%

Section: Resultsmentioning

confidence: 49%

Miniaturized CO₂ Gas Sensor Using 20% ScAlN-Based Pyroelectric Detector

Liang

Chen

et al. 2022

ACS Sens.

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“…Additionally, the pyroelectric property is also enhanced in ScAlN, with up to a 25%-85% increase in effective pyroelectric coefficient compared to pure AlN [133,134]. A detailed study by Kurz et al indicates the additional external stress from the substrate, namely the clamping pyroelectric component, is the major contributor of effective pyroelectric coefficient, while the primary and secondary pyroelectric effects have opposite signs and only contributes negligible pyroelectric charge, which are beneficial for stabilizing electroacoustic device operation [135].…”

Section: Piezoelectricitymentioning

confidence: 99%

Dawn of nitride ferroelectric semiconductors: from materials to devices

Wang

Mondal

et al. 2023

Semicond. Sci. Technol.

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III-nitride semiconductors are promising optoelectronic and electronic materials and have been extensively investigated in the past decades. New functionalities, such as ferroelectricity, ferromagnetism, and superconductivity, have been implanted into III-nitrides to expand their capability in next-generation semiconductor and quantum technologies. The recent experimental demonstration of ferroelectricity in nitride materials, including ScAl(Ga)N, BAlN, and hBN, has inspired tremendous research interest. Due to the large remnant polarization, high breakdown field, high Curie temperature, and significantly enhanced piezoelectric, linear, and nonlinear optical properties, nitride ferroelectric semiconductors have enabled a wealth of applications in electronic, ferroelectronic, acoustoelectronic, optoelectronic, and quantum devices and systems. In this review, the development of nitride ferroelectric semiconductors from materials to devices is discussed. While expounding on the unique advantages and outstanding achievements of nitride ferroelectrics, the existing challenges and promising prospects have been also discussed.

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