Electrical characteristics of metal-dielectric-metal and metal-dielectric-semiconductor structures based on electron beam evaporated Y2O3, Ta2O5 and Al2O3 thin film
V. Mikhaelashvili et al., Electrical characteristics of metal-dielectric-metal and metal-dielectric-semiconductor structures based on electron beam evaporated Y2O3, Ta2O5 and Al2O3 thin film, J APPL PHYS, 84(12), 1998, pp. 6747-6752
This work examines the electrical properties of metal-dielectric-semiconduc
tor (Au/Ti-D-pSi) and metal-dielectric-metal (Au/Ti-D-Pt/Ti-pSi) capacitors
which incorporate as dielectrics Y2O3, Al2O3 and Ta2O5 films evaporated by
an electron beam at room temperature. The emphasis of the results is twofo
ld: the first is the high quality of the investigated films as evidenced by
the small measured values of loss factor, flatband voltages, and surface s
tates density as well as the low dispersion of the relative dielectric cons
tants. The second is an analytical procedure for discrimination of current
flow mechanisms, under different regimes of applied voltage. A detailed stu
dy of the power exponent parameter a = d (Log I)/d(Log V) was found to be s
uperior to conventional graphical representation of I - V data. The dominan
t mechanisms of charge transport through the metal-dielectric-metal structu
res was found to be the Schottky emission for Y2O3, and Al2O3 at low electr
ical fields. For structures with Y2O3 and Ta2O5 films operating in the high
field regime, the charge transport mechanism is mainly space charge limite
d current. (C) 1998 American Institute of Physics. [S0021-8979(98)01723-X].