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Effect of SiO 2 interlayer on the properties of Al 2 O 3 thin films grown by plasma enhanced atomic layer deposition on 4H‐SiC substrates
Author(s) -
Schilirò E.,
Fiorenza P.,
Di Franco S.,
Bongiorno C.,
Saggio M.,
Roccaforte F.,
Lo Nigro R.
Publication year - 2017
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201600365
Subject(s) - materials science , atomic layer deposition , dielectric , amorphous solid , thin film , substrate (aquarium) , optoelectronics , current density , field effect transistor , field effect , analytical chemistry (journal) , transistor , nanotechnology , voltage , electrical engineering , crystallography , chemistry , oceanography , physics , engineering , quantum mechanics , chromatography , geology
Al 2 O 3 films were grown by plasma enhanced‐atomic layer deposition (PE‐ALD) on 4H‐SiC substrates, with and without the presence of a thin SiO 2 layer. The collected data indicated the formation of amorphous, adherent, and uniform Al 2 O 3 thin films with a thickness of about 30 nm. The electrical characterization has been performed on metal–oxide–semiconductor (MOS) structures by both capacitance–voltage ( C – V ) and current–voltage ( I – V ) measurements. All these analyses demonstrated a better dielectric behavior of the Al 2 O 3 film deposited on the SiO 2 /SiC stack, with respect to that deposited directly on the SiC substrate. In particular, higher dielectric constant value, lower leakage current density, and higher breakdown field have been found in the Al 2 O 3 /SiO 2 /SiC stack. Hence, it has been argued that the presence of the interfacial SiO 2 provides a better condition for the growth of high quality Al 2 O 3 films. In this context, the film density has been evaluated, and strong difference has been found in the density values, The correlation between the better electrical properties of the Al 2 O 3 films on SiO 2 and their higher density has been demonstrated. These results provide useful insights on the possible application of these Al 2 O 3 films as gate insulator in 4H‐SiC metal‐oxide‐semiconductor field effect transistors.