Influence of Y2O3 Doped HfO2 High-k Films on Electrical Properties of MOS and MIM Devices

Y
2
O
3
doped HfO
2
high-k films were successfully fabricated on P-type and N-type doped Si substrates by liquid phase deposition (LPD) for metal-oxide-semiconductor (MOS) and metal-insulator-metal (MIM) capacitors. The effects of doping different molar concentrations of Y
2
O
3
and nitrogen annealing on the electrical properties of HfO
2
thin films were investigated, too. According to the experimental results, the HfO
2
film doped with Y
2
O
3
(5 mol%) had a high capacitance density and low leakage current. The improvement of defects at low-temperature deposited films was achieved by using nitrogen annealing at 600°C. The oxide capacitance of the MOS capacitor is 127 pF, approaching the ideal flat-band voltage of -0.53 V, small hysteresis flat band voltage of 0.093 V, and low leakage current density of 3.78 × 10
^-5
A/cm
²
at +5 V. The capacitance density of MIM capacitors at 1 MHz is 2.98 fF/µm
²
, small relatively quadratic voltage coefficient of capacitance (VCC) of -517.96 ppm/V
²
, and leakage current density 1.12 × 10
^-2
A/cm
²
at +3 V. Therefore, Y
2
O
3
doped HfO
2
films can be applied in MOSFET, radio frequency, and mixed-signal integrated circuits as a promising candidate to replace SiO
2
.