Effect of phase transition on structural, dielectric, and electrical properties of pulsed laser deposited Y doped high-k HfO2 thin films

Yttrium doped hafnia (Y-doped HfO2) thin film based devices have recently shown their potential for advanced nanoelectronics applications. Here, we report the fabrication of device-grade Hf(1−x)YxO2 (x = 0, 0.10, and 0.20) thin films on both Si(100) and platinized silicon substrates using an optimized Nd:YAG pulsed laser deposition system, wherein detailed structural and compositional characterizations were carried out to establish a structural-dielectric property correlation. The capacitance-frequency (C–F), capacitance-voltage (C–V), and current-voltage (I–V) measurements of these as-grown films were carried out in Pt top-bottom electrode-based metal-insulator-metal capacitor configuration. The increase in high frequency (1 MHz) dielectric constant values from ∼24 to 38, with an increase in Y doping from x = 0 to 0.20, is assigned to the phase transition from pure monoclinic to pure cubic configuration, as confirmed from grazing incidence x-ray diffraction and high resolution transmission electron microscopy measurements. However, the increment in low-frequency dielectric loss (at 100 Hz) and leakage current density values (at 1 V applied bias) from ∼0.6 to 35 and from ∼2.5 × 10−5 to 5.3 × 10−3 A/cm2, respectively, with increasing Y doping is attributed to the enhancement in yttrium-induced oxygen vacancy concentration in the hafnia matrix, as confirmed by x-ray photoelectron spectroscopy measurements. These tailorable device parameters make Y-doped hafnia a promising candidate for next-generation nanoelectronics applications.