Characterization of AlN films deposited by r.f. reactive sputtering aiming MEMS applications

Abstract

Aluminium Nitride (AlN) films deposited by reactive r.f. magnetron sputtering, of a pure aluminium target in an argon (Ar) / nitrogen (N2) mixture atmosphere, onto Si (100) and Si (111) substrates are studied. A series of samples was obtained varying the Ar and N2 gaseous mixture maintaining the process pressure fixed. The AlN films were characterized by FTIR, X‐ray diffraction, visible optical absorption, ellipsometry and stress measurements. X‐ray results showed a preferential orientation in the planes (100) and (002). Films obtained in an Ar rich atmosphere presented only one vibration mode corresponding to a composition of the AlN A1 (TO) and E1 (LO) modes. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Mechanical, Corrosion and Biological Properties of Room-Temperature Sputtered Aluminum Nitride Films with Dissimilar Nanostructure

“…The sputtering pressure and working atmosphere conditions have been chosen based on our previous experience, when found optimal for the growth of c -axis textured films. They are, in many respects, similar to kindred works in this research field [ 43 , 44 , 45 , 46 , 47 , 48 ]. A lower sputtering pressure was preferred as it assures an increased kinetic energy transfer from plasma to the growing films surface [ 48 ], thus accommodating good crystalline quality.…”

“…The features of sputtered layers can be engineered by tailoring the deposition conditions [ 42 ]. The survey of scientific literature unveils that the synthesis of highly c -axis textured AlN films can be achieved by MS for the most part in low total sputtering pressure (i.e., 0.2–0.5 Pa [ 43 , 44 , 45 , 46 , 47 , 48 ]) and nitrogen-in-argon dilution conditions (i.e., 20–50%) [ 43 , 44 , 45 , 46 , 47 , 48 ] (with the exception of pulsed direct-current regime where higher nitrogen volumetric concentrations are needed (i.e., >50%) [ 47 ]); whereas, the target-to-substrate separation distance, substrate temperature and target powder densities vary significantly in the ranges 20–120 mm, 80–650 °C, and 0.018–0.150 W/mm 2 [ 43 , 44 , 45 , 46 , 47 , 48 ], respectively. A new emerging solution for growing high quality c -axis oriented AlN is the two-step sputtering which implies the insertion at the substrate—prospect AlN coating interface of a thin AlN seed layer synthesized at an elevated temperature (e.g., 450 °C), followed by the deposition at a lower temperature of the bulk AlN layer [ 41 , 49 ].…”

Estrutura de microlâmpadas energizadas em escala micrométrica

“…Detalhes da fabricação do dispositivo são descritos no capítulo 3. Dado que o GNMD possui larga experiência na deposição de filmes finos extensos sobre diversos substratos utilizando PECVD e pulverização catódica (sputtering) [19][20][21][22][23][24][25][26][27][28] , a microlâmpada analisada neste trabalho foi produzida utilizando tais técnicas, bem como demais processos de microfabricação, conforme descrito a seguir.…”

“…Diversos estudos sobre filmes de AlN estão disponíveis na literatura. Nas deposições por sputtering, dependendo das condições, a estrutura obtida pode ser amorfa ou wurtzita [23,53] . A fase zinc blende estável foi obtida em filmes muito finos (1,5 ≠ 2,0 nm) [45] , e a rock salt foi estabilizada em filmes crescidos epitaxialmente em condições especiais [54] .…”

“…A razão mais provável para a as modificações estruturais da microlâmpada de a-SiC, indicam a presença da fase wurtzita [23] .…”