Impact of the substrate dependent polarity distribution in c-axis oriented AlN thin films on the etching behaviour and the piezoelectric properties

Wistrela, E.; Schneider, Michael; Bittner, A.; Schmid, U.

doi:10.1007/s00542-015-2799-6

Cited by 10 publications

(4 citation statements)

References 35 publications

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“…Scanning Kelvin probe microscopy (SKPM) is a nondestructive method used to identify thin film polarities, as compared to wet etching and TEM [72,99,100]. As illustrated in figure 12, surface potentials were collected by scanning the LPS sample either in dark conditions or under UV illumination [99].…”

Section: Methods To Identify Polarity and Related Mechanismsmentioning

confidence: 99%

Polarity control and fabrication of lateral polarity structures of III-nitride thin films and devices: progress and prospects

Guo

Chen

et al. 2020

J. Phys. D: Appl. Phys.

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Due to their non-centrosymmetric crystal orientation, wurtzite III-nitride crystals have two distinct orientations, i.e. III-polar and N-polar along the c-axis. Extensive effort has been devoted to polarity control and the characterization of III-nitride thin films. Both III-polar and N-polar films possess some unique features. By taking full advantage of both III and N-polar domains in a single structure, a lateral polarity structure (LPS), where III-polar and N-polar domains are grown side-by-side simultaneously on the wafer, has attracted great interest. In this review, recent progress in the design and fabrication of III-nitride LPS on various substrates is summarized. The structural, optical and electronic properties of III-nitride thin films incorporating LPS are discussed, with special attention paid to the interface between adjacent domains. Various techniques to qualitatively and quantitatively identify the polarity domains are provided, and their applications in optoelectronic and electronic devices including light-emitting-diodes, nonlinear frequency doubling waveguides, Schottky-barrier-diodes, etc, are intensively elaborated on. Finally, challenges related to the development of LPS-based devices and future perspectives are presented.

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Section: Methods To Identify Polarity and Related Mechanismsmentioning

confidence: 99%

Polarity control and fabrication of lateral polarity structures of III-nitride thin films and devices: progress and prospects

Guo

Chen

et al. 2020

J. Phys. D: Appl. Phys.

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“…Al target (purity 5N) at fixed deposition parameters at a chamber pressure of p ¼ 2 lbar and a plasma power of P ¼ 800 W in a pure nitrogen atmosphere. 30,31 Double sided polished monocrystalline 350 lm thick n-type silicon (Si) wafers diced into pieces of (8 Â 8) mm 2 serve as substrate material. Prior each deposition, the Si samples are cleaned by rinsing in acetone and subsequently in isopropanol.…”

Section: Methodsmentioning

confidence: 99%

“…Thereby, the error bars represent the maximum deviation from the mean value considering eight single measurements. To avoid cracking of the layer due to an increased residual film stress, the deposition time is adjusted such that the substrate temperature does not exceed 175 C. 30 To investigate the thin film morphology and film thickness, scanning electron microscope (SEM) analyses are performed using a Hitachi SU 8030 operating at an accelerating voltage of 2 kV. The Cr content within the AlN thin films is measured by energy dispersive X-ray spectroscopy (EDX) using a SEM integrated Oxford Instruments X-Max 50 mm 2 system at a beam energy of 15 keV and a tilting angle of 30 towards the EDX detector.…”

Section: Methodsmentioning

confidence: 99%

Magnetic and microstructural properties of sputter deposited Cr-doped aluminum nitride thin films on silicon substrates

Wistrela

Bittner

Schneider

et al. 2017

Journal of Applied Physics

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In this paper, we report on the microstructural and magnetic properties of CrxAl1−xN thin films with Cr concentrations ranging up to x = (8.5 ± 0.5) at. %. The thin films are sputter deposited on silicon substrates and exhibit a wurtzite type microstructure verified by X-ray diffraction measurements. A vibrating sample magnetometer based measurement equipment is used to investigate magnetic properties of the Cr doped thin films in a temperature range of T = 10 K–300 K, revealing a paramagnetic behavior. With increasing temperature, the temperature independent diamagnetic contribution of the substrate material dominates the overall response characteristics. No room temperature ferromagnetism is observed for all samples investigated.

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“…The highly c-axis-oriented growth of AlN thin films is known to be essential for obtaining high piezoelectric coefficients [12]. Therefore, many researchers have devoted considerable effort to developing highly c-axis-oriented AlN thin films with high crystalline quality [13][14][15][16][17][18][19][20]. Epitaxial growth is an attractive method to realize this, and c-plane sapphire is one of the most practical and widely used substrates due to a reasonable lattice mismatch (around 13%) and cost [21,22].…”

Section: Introductionmentioning

confidence: 99%

Low-Temperature Epitaxial Growth of AlN Thin Films on a Mo Electrode/Sapphire Substrate Using Reactive Sputtering

Kim

2021

Coatings

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High-crystalline aluminum nitride (AlN) thin films are essential for device applications, and epitaxial growth is a promising approach to improve their crystalline quality. However, a high substrate temperature is usually required for the epitaxial growth, which is not compatible with the complementary metal-oxide-semiconductor (CMOS) process. Furthermore, it is very difficult to obtain epitaxial AlN thin films on the deposited metal layers that are sometimes necessary for the bottom electrodes. In this work, epitaxial AlN thin films were successfully prepared on a molybdenum (Mo) electrode/sapphire substrate using reactive sputtering at a low substrate temperature. The structural properties, including the out-of-plane and in-plane relationships between the AlN thin film and the substrate, were investigated using X-ray diffraction (XRD) 2θ-ω, rocking curve, and pole figure scans. Additional analyses using scanning electron microscopy (SEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM) were also carried out. It was shown that highly c-axis-oriented AlN thin films were grown epitaxially on the Mo/sapphire substrate with an in-plane relationship of AlN [112¯0]//sapphire [101¯0]. This epitaxial growth was attributed to the highly ordered and oriented Mo electrode layer grown on the sapphire substrate. In contrast, the AlN deposition on the Mo/SiO2/Si substrate under the same conditions caused poorly oriented films with a polycrystalline structure. There coexisted two different low-crystalline phases of Mo (110) and Mo (211) in the Mo layer on the SiO2/Si substrate, which led to the high mosaicity and polycrystalline structure of the AlN thin films.

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Impact of the substrate dependent polarity distribution in c-axis oriented AlN thin films on the etching behaviour and the piezoelectric properties

Cited by 10 publications

References 35 publications

Polarity control and fabrication of lateral polarity structures of III-nitride thin films and devices: progress and prospects

Polarity control and fabrication of lateral polarity structures of III-nitride thin films and devices: progress and prospects

Magnetic and microstructural properties of sputter deposited Cr-doped aluminum nitride thin films on silicon substrates

Low-Temperature Epitaxial Growth of AlN Thin Films on a Mo Electrode/Sapphire Substrate Using Reactive Sputtering

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