Evaluation of the Capacitances by Using High Frequency Roll-Off Fitting to the Second Order Approximation
The characteristics and feasibility of the dielectric can be evaluated by the deposition of the dielectric in between two electrodes to form a capacitor. In metal-insulator-silicon (MIS) structure, 100 Å Ta2O5 films are deposited on 1000 Å doped poly silicon as a bottom electrode layer and 500 Å TiN metal on top of the dielectric film consecutively . The measured capacitances of larger areas roll off at higher measuring frequency . With the setting of an equivalent circuit, one successfully explains why the roll-off effect shows up. The deduced formulas give the common, reasonable, and convincing C1=1.1255×10-5 nF/mm2, which determines the equivalent dielectric (oxide) thickness 30.5Å.
Helen Zhang, Gang Shen and David Jin
H. C. Yang and M. C. Wang, "Evaluation of the Capacitances by Using High Frequency Roll-Off Fitting to the Second Order Approximation", Advanced Materials Research, Vols. 204-210, pp. 554-557, 2011