Dielectric breakdown of alumina thin films produced by pulsed direct current magnetron sputtering

THIN SOLID FILMS

卷:662

Article

Hanby, Benjamin V. T.¹  Stuart, Bryan W.¹  Grant, Colin³  Moffat, Jonathan⁴  Blissett, Jonathan²  Gerada, Chris²  Gimeno-Fabra, Miquel¹  Grant, David M.¹ 

[1] Univ Nottingham, Fac Engn, Adv Mat Res Grp, Nottingham NG7 2RD, England

[2] Univ Nottingham, Fac Engn, Power Elect Machines & Control Res Grp, Nottingham NG7 2RD, England

[3] Hitachi High Technol, Whitebrook Pk, Maidenhead SL6 8YA, Berks, England

[4] Asylum Res, Oxford Instruments, High Wycombe HP12 3SE, Bucks, England

关键词: Alumina;    Magnetron sputtering;    Pulsed;    Dielectric strength;    Adhesion;   

DOI  :  10.1016/j.tsf.2018.07.004

来源: Elsevier

【 摘 要 】

Alumina films (similar to 2 mu m thick) were deposited with a mixed Cu/Al interlayer onto copper. Direct current (DC)/ Pulsed DC (PDC) magnetron sputtering techniques were independently compared for reactive alumina sputtering. In DC sputtered films, elemental aluminium of 9.2 at.% and nano-crystallites were present within the x-ray amorphous matrix, resulting from target arcing. Defects lead to premature dielectric breakdown/increased current leakage. PDC sputtering improved film quality by removing crystallites, metallic clusters and through thickness cracking. Time dependent dielectric breakdown (TDDB) measurements were carried out using conductive atomic force microscopy identified an improvement in dielectric strength (166 to 310 V mu m(-1)) when switching from DC to PDC deposition power. TDDB suggested that at high applied field the dominant prebreakdown conduction mechanism was Fowler-Nordheim tunnelling in DC films. Tensile pull-off adhesion ranged from 56 to 72 MPa and was highest following incorporation of an Cu/Al blended interfacial layer. Scratch testing indicated various cracking/buckling failures.

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