Regensburg 2019 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 35: HL Poster II

HL 35.6: Poster

Wednesday, April 3, 2019, 17:30–20:00, Poster E

Spectroscopic characterization of sputtered ScAlN thin films — •Tim Hofmann¹, Katja Tonisch¹, Bernd Hähnlein¹, Jaroslav Kovic Jr.², Jörg Pezoldt¹, and Stefan Krischok¹ — ¹TU Ilmenau, Ehrenbergstr. 29, 98693 Ilmenau — ²Slovak University of Technology, Ilkovicova 3, Bratislava 81219, Slovakia

Wide-bandgap semiconductors represent an attractive option to meet the demands of microelectromechanical systems (MEMS). Especially aluminum nitride (AlN) is the material of choice when it comes to integrated MEMS structures for sensing, actuating and energy harvesting applications requiring a piezoelectric thin film. However, next to a low electromechanical coupling coefficient, the piezoelectric response is much lower than that of PZT, both facts limiting the scope of possible applications. Thus, increasing interest concentrates on a new, recently emerging ternary nitride alloy, namely scandium aluminum nitride or Sc(x)Al(1-x)N, whose piezoelectric response is reported to increase 5-fold for x = 0.3 compared to that of pure AlN. Next to its piezoelectric properties, also the structural, mechanical, electrical and optical properties need to be understood to implement ScAlN into new technological concepts. We analyzed the dependency of the built-in strain on the Scandium content for sputtered ScAlN thin films with a maximum Scandium content of x = 0.25 by X-ray diffraction. Additional Raman spectroscopy and infrared spectroscopy showed a strain dependent shift of the observed optical phonon modes in accordance with the XRD measurements. The stoichiometry of all samples was determined by X-ray photoemission spectroscopy.