Annealing effect on electrical properties of high-k MgZnO film on silicon

Cubic crystalline MgZnO was grown on p-type Si (0 0 1) by a reactive e-beam evaporation system at low temperature. AES depth profiles for the MgZnO films demonstrate good uniformity of Mg, Zn and O components. MIS capacitors were fabricated and C-V and I-V characterizations were performed to evaluate the annealing effect on electrical properties of MgZnO films. High temperature annealing up to 900 degrees C under O-2 ambient significantly improves C-V and I-V characteristics. The interface trapped charges decrease from 5.30 x 10(12) cm(-2) to 2.48 x 10(11) cm(-2) as the annealing temperature increases from 550 degrees C to 900 degrees C, indicating the quality improvement of the interfacial layer. Meanwhile the density of mobile charges increases from 1.93 x 10(10) cm(-2) to 1.72 x 10(11) cm(-2) as the annealing temperature increases from 550 degrees C to 900 degrees C, which is attributed to the evaporation of O near the surface and migration of Zn2+ towards the surface from MgZnO alloy film under such high temperatures.