Zinc oxide grown by Atomic Layer Deposition - a material for novel 3D electronics
|Elżbieta Guziewicz 1, Marek Godlewski 1,2, Nolwenn Huby 3, Milka Kutrzeba 3, Grazia Tallarida 3, Tomasz A. Krajewski 1, Łukasz Wachnicki 1, Krzysztof Kopalko 1, Grzegorz Łuka 1, Jaroslaw Domagala 1, Wojciech Paszkowicz 1, Bogdan J. Kowalski 1, Bartłomiej S. Witkowski 2, Ewa Przezdziecka 1|
1. Polish Academy of Sciences, Institute of Physics, al. Lotników 32/46, Warszawa 02-668, Poland
Last years miniaturization of semiconductor devices encountered obstacles to scale below the 65 nm mode, because of a high parasitic current in a dominant floating gate architecture. Therefore in 2007 for the first time high-k oxides replaced silicon oxide, which enables scaling of the device to the 45 nm mode. However, further scaling below 22 nm mode requires changing of the device architecture from planar to three-dimensional. This imposes critical restrictions on growth and processing temperature as using of metal passes at the back of the line (BEOL architecture) limit processing temperature to 350 0C. The silicon technology requires processing temperature at the level of 1000 0C and cannot be used in this case. Therefore we observe a booming interest in semiconductor materials, which can be successfully grown at low temperature.
Our investigations show that zinc oxide is a very good candidate for a low temperature electronics. ZnO thin films are grown by Atomic Layer Deposition using organic compounds as zinc precursors. Thanks to these volatile precursors we were able to investigate a low growth temperature range between 1000C and 3000C. The obtained zinc oxide films are monocrystalline when deposited on gallium nitride substrate and growth temperature is higher than 2500C. We show that even without external doping a free carrier concentration in these films can be reproducibly controlled in the wide range (form 1015cm-3 to 1021cm-3), which is a basic requirement for electronic applications. Our investigations show that ZnO grown at low temperature by ALD is a prospective material for novel low temperature electronic applications such as 3D structures and organic/inorganic heterojunctions.
The work was partially supported by EU within the European Regional Development Found through grant Innovative Economy No. POIG.01.01.02-00-008/08.
Presentation: Invited oral at E-MRS Fall Meeting 2009, Symposium C, by Elżbieta Guziewicz
See On-line Journal of E-MRS Fall Meeting 2009
Submitted: 2009-05-08 13:58 Revised: 2013-02-28 15:04