Impact of post-deposition annealing on surface, bulk and interface properties of RF sputtered AlN films
TL;DR: In this paper, C axis oriented AlN films were deposited on silicon substrate by radio frequency reactive magnetron sputtering and then the films were annealed in a horizontal furnace at temperatures ranging from 400 to 800°C for 30 min in nitrogen ambient.
Abstract: C axis oriented AlN films were deposited on silicon substrate by radio frequency reactive magnetron sputtering. Subsequently the films were annealed in a horizontal furnace at temperatures ranging from 400 to 800°C for 30 min in nitrogen ambient. The change in the morphological properties with annealing temperatures was investigated using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and atomic force microscopy techniques. Morphological studies revealed that the annealing increased surface roughness and grain size. In addition, Al–N bond density along with the crystallinity of the deposited films was improved with annealing. The electrical properties, namely the insulator charge density (Q in) and the interface electronic state density (D it), were estimated by the capacitance–voltage (C–V) measurements. It was found that the Q in increased, but the D it decreased with annealing temperature. Lower leakage current with improved resistivity and dielectric b...
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TL;DR: In this paper, a review of recent studies of AlN structures, focusing on their fabrication and novel applications, is presented, along with various fabrication techniques used to synthesize AlN films and their growth mechanisms and crystal structure.
125 citations
TL;DR: In this article, the authors discuss piezoelectric acoustic devices based on widely used PDE materials and the influence of process parameters on the growth, texture and orientation of the films are discussed.
Abstract: This paper discusses piezoelectric acoustic devices based on widely used piezoelectric materials. Commonly used piezoelectric thin film deposition techniques and the influence of process parameters on the growth, texture and orientation of the films are discussed. Etching techniques are also outlined. A comparative study of different devices developed previously is given. Also, applications of developed devices in aero-acoustic and medical fields have been briefly discussed. Flow charts of various techniques of deposition along with a combined one for full acoustic device fabrication are given. Various techniques, frequently used for thin film characterization have been discussed. The testing and measurement techniques to determine the responses of acoustic devices such as sensitivity, resonance frequency, frequency response, piezoelectric co-efficient etc. have been briefly illustrated. This paper discusses common failure modes with respect to the field of use of acoustic devices. It also concisely discusses various reliability tests done in industries to assess the quality of the developed devices. This review has also suggested directions for future development of thin film acoustic sensors.
88 citations
01 Jun 2012-Microsystem Technologies-micro-and Nanosystems-information Storage and Processing Systems
TL;DR: In this article, a comprehensive study on the complete process for the fabrication of AlN-based MEMS sensors and actuators is presented, where the influence of the bias voltage on the whole set of piezoelectric parameters was investigated.
Abstract: A comprehensive study on the complete process for the fabrication of AlN-based MEMS sensors and actuators is presented. Varying the bias voltage during the reactive rf sputtering enables to adjust the stress level in AlN films in the range of about 2 GPa. For the first time the influence of the rf bias power on the whole set of piezoelectric parameters was investigated. It could be shown that the dielectric permittivity, dielectric loss, rocking curve width, effective longitudinal piezoelectric coefficient d 33,f and effective transverse piezoelectric coefficient e 31,f remained unchanged. Further it was observed that piezoelectric AlN films could be deposited at low process temperatures of only 200 °C. Moreover an increase in the e 31,f coefficient with thicker films could be stated. Finally cone formation during wet etching was observed and revealed a formation of {01–12} planes which exhibit a slow etching rate. The c-textured growth of AlN starts directly at the Pt interface.
33 citations
TL;DR: In this article, the thermal annealing process of sputtered AlN films with different thicknesses on sapphire substrates was studied in N2 ambient, and the results showed that the crystal quality of these AlN film was significantly improved after 1400-1700 ǫ°C anneal.
Abstract: Thermal annealing process of sputtered AlN films with different thicknesses on sapphire substrates was studied in N2 ambient. Crystal quality of these AlN films was significantly improved after 1400–1700 °C annealing. For the 200-nm AlN film, the full width at half maximum (FWHM) of the (0002)-plane X-ray rocking curve (XRC) was improved from 157.3 to 103.6 arcsec after 1650 °C annealing, while the FWHM of the (10
$$\bar {1}$$
2)-plane XRC was significantly improved from 3890 to 353.1 arcsec. Transmission electron microscopy further confirmed that the crystal quality improvement was related to solid-phase reaction at high temperature, allowing columnar structure AlN to recrystallize and thus reducing threading dislocations in the films. Surface morphology with high-density AlN islands transformed to step-and-terrace morphology. X-ray photoelectron spectroscopy measurement also indicated that C and O impurities were decreased by the thermal annealing process. Film strain changed from tensile to compressive stress after annealing. The optical transmissivities of these AlN films did not decrease after annealing, and the optical transmissivity band edge slopes increased, providing further evidence of improved crystal quality.
29 citations
TL;DR: In this paper, C axis oriented AlN films were deposited on silicon substrate by radio frequency reactive magnetron sputtering and then the films were annealed in a horizontal furnace at temperatures ranging from 400 to 800°C for 30 min in nitrogen ambient.
Abstract: C axis oriented AlN films were deposited on silicon substrate by radio frequency reactive magnetron sputtering. Subsequently the films were annealed in a horizontal furnace at temperatures ranging from 400 to 800°C for 30 min in nitrogen ambient. The change in the morphological properties with annealing temperatures was investigated using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and atomic force microscopy techniques. Morphological studies revealed that the annealing increased surface roughness and grain size. In addition, Al–N bond density along with the crystallinity of the deposited films was improved with annealing. The electrical properties, namely the insulator charge density (Q in) and the interface electronic state density (D it), were estimated by the capacitance–voltage (C–V) measurements. It was found that the Q in increased, but the D it decreased with annealing temperature. Lower leakage current with improved resistivity and dielectric b...
15 citations
References
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Book•
18 Mar 1982
TL;DR: In this article, the authors present a method for extracting interface trap properties from the conductance of a metal oxide Silicon Capacitor at intermediate and high frequency intervals, and demonstrate that these properties can be used for charge trapping in the oxide.
Abstract: Introduction. Field Effect. Metal Oxide Silicon Capacitor at Low Frequencies. Metal Oxide Silicon Capacitor at Intermediate and High Frequencies. Extraction of Interface Trap Properties from the Conductance. Interfacial Nonuniformities. Experimental Evidence for Interface Trap Properties. Extraction of Interface Trap Properties from the Capacitance. Measurement of Silicon Properties. Charges, Barrier Heights, and Flatband Voltage. Charge Trapping in the Oxide. Instrumentation for Measuring Capacitor Characteristics. Oxidation of Silicon--Oxidation Kinetics. Oxidation of Silicon--Technology. Control of Oxide Charges. Models of the Interface. Appendices. Subject Index. Symbol Index.
2,101 citations
01 Jan 1982
TL;DR: In this article, the authors present a method for extracting interface trap properties from the conductance of a metal oxide Silicon Capacitor at intermediate and high frequency intervals, and demonstrate that these properties can be used for charge trapping in the oxide.
Abstract: Introduction. Field Effect. Metal Oxide Silicon Capacitor at Low Frequencies. Metal Oxide Silicon Capacitor at Intermediate and High Frequencies. Extraction of Interface Trap Properties from the Conductance. Interfacial Nonuniformities. Experimental Evidence for Interface Trap Properties. Extraction of Interface Trap Properties from the Capacitance. Measurement of Silicon Properties. Charges, Barrier Heights, and Flatband Voltage. Charge Trapping in the Oxide. Instrumentation for Measuring Capacitor Characteristics. Oxidation of Silicon--Oxidation Kinetics. Oxidation of Silicon--Technology. Control of Oxide Charges. Models of the Interface. Appendices. Subject Index. Symbol Index.
1,855 citations
10 Apr 2003
TL;DR: In this article, the relationship between sputter deposition conditions, AlN film structure, electromechanical coupling factor kt, and relevant electrical parameters of BAW devices are discussed, as well as their relationship with BAW resonators and filters.
Abstract: Thin film bulk acoustic wave (BAW) resonators and filters are well suited for mobile communication systems operating at high frequencies between 0.5 and 10 GHz. Piezoelectric thin film materials investigated for BAW devices within Philips include AlN thin films. The relationship between sputter deposition conditions, AlN film structure, electromechanical coupling factor kt, and relevant electrical parameters of BAW devices are discussed.
150 citations
TL;DR: The effect of doping and annealing on the optical and structural properties of single-crystal ZnO films has been investigated by means of X-ray diffraction (XRD), photoluminescence (PL) spectrum and atomic force microscopy (AFM) as mentioned in this paper.
135 citations
TL;DR: An experimental method for observing the saturation of the Poole-Frenkel (PF) effect in insulating films is developed, allowing observation of this theoretically predicted effect for the first time as mentioned in this paper.
122 citations