Electrical characterization of capacitors with AVD-deposited hafnium silicates as high-k gate dielectric

We discuss the electrical properties of hafnium silicates with various composition deposited by atomic vapor deposition (AVD) as metal-oxide-semiconductor (MOS) capacitors. The deposited layers demonstrate well-behaved capacitance as function of gate voltage (CV) curves with a leakage as low as 5 X 10(-2) for an equivalent oxide thickness (EOT) of 1.3 nm. The permittivity (k-value) ranges from 6 to 14 depending on the composition of the hafnium silicate. Flatband voltage depends on the composition (and thickness) and varies between -0.10 and 0.45 V, from which we calculated the amount of net charge in the layer, between (-6 +/- 3)X10(11) and (20 +/- 3)X10(11)/cm(2). Postdeposition treatments at 800 degrees C in O-2 or NH3 shift the V-FB position up to 100 mV, together with a change of the amount of net charge. Fine-tuning the deposition and composition might nullify the net charge contribution in the layers. (c) 2005 The Electrochemical Society. All rights reserved.