Novel hysteresis effect in ultrathin epitaxial Gd₂O₃ high-k dielectric

Charge trapping in ultrathin high-k Gd₂O₃ dielectric leading to appearance of hysteresis in C–V curves is studied by capacitance-voltage, conductance-frequency and current-voltage techniques at different temperatures. It was shown that the large leakage current at a negative gate voltage causes the reversible trapping of the positive charge in the dielectric layer, without electrical degradation of the dielectric and dielectricsemiconductor interface. The capture cross-sections of the hole traps are around 10⁻¹⁸ and 2 × 10⁻²⁰ cm² . The respective shift of the C–V curve correlates with a “plateau” at the capacitance corresponding to weak accumulation at the silicon interface

Enhanced reliability and capacitance stability of ZrO2-based decoupling capacitors by interface doping with Al2O3

ZrO2-based metal-insulator-metal (MIM) capacitors are manufactured using atomic layer deposition. The impact of aluminum doping at the electrode interface on the electrical characteristics is evaluated using I-V, C-V and time dependent dielectric breakdown measurements. The aluminum doping profiles are examined using ToF-SIMS. Further, the impact of electrical stress and temperature on the C-V characteristic is analyzed. Experimental results indicate that charge trapping at the electrode vicinity is responsible for capacitance degradation effects. The incorporation of aluminum has a positive effect on breakdown voltage, lifetime, capacitance stability, and suppresses the formation of hysteresis effects

Ultra-Thin high density capacitors for advanced packaging solutions

The growing demand on small system solutions is driving the compression of many functions into small package outline. This requires sophisticated solutions to avoid external circuitry area when integrating passive components. Moreover, decoupling capacitors need to be placed as close as possible to the active circuits in order to suppress cross-coupling between different power planes efficiently. In our paper we present the concept, fabrication and characterization results of ultra-Thin silicon capacitors that can be integrated into chip package or embedded in PCB. High capacitance densities are achieved by using high-k materials as dielectric supporting a broad application range from RF-filtering to decoupling and energy buffering. Based on characterization results of voltage and temperature characteristics it is shown that this concept offers good electrical properties and linearity compared to conventional ceramic capacitors, like MLCC

High-K metal gate stacks with ultra-thin interfacial layers formed by low temperature microwave-based plasma oxidation

Ultra-thin interfacial silicon oxide layers are grown by microwave-based plasma oxidation at temperatures below 200 °C. The influence of plasma gas composition and plasma pulsing on layer properties is tested. The oxides are compared to standard thermally grown oxide and wet chemical oxide. Layer properties are evaluated by x-ray photo electron spectroscopy and are electrically characterized by means of TiN/HfO2/SiO2 high-k metal gate stacks

Low-temperature microwave-based plasma oxidation of Ge and oxidation of silicon followed by plasma nitridation

In the semiconductor industry Germanium is expected as the promising channel material for future high-mobility CMOS transistors because of its highest hole mobility among common elemental and compound semiconductors, and an electron mobility that is two times larger than that of Si. This article shows that oxides can be grown and/or in a subsequent process step nitridized for planar Ge and Si devices at very low temperatures (T < 460°C). The stable oxide growth on Germanium through plasma processing is studied as a function of relevant processing parameters like time, gaseous ambient etc. For Silicon the bonding structure of pure and nitridized low-temperature grown SiO2 is analyzed, followed by an electrical characterization of 0.8 to 1.2 nm interfacial layers on Si

Reliability improvements of TiN/Al2O3/TiN for linear high voltage metal-insulator-metal capacitors using an optimized thermal treatment

Metal–insulator–metal (MIM) capacitors with TiN and high thickness of Al2O3 above 50 nm were fabricated to address high voltage (>30 V) and linear capacitor applications. Atomic layer deposition is used to deposit both TiN and Al2O3 to guarantee a good composition and thickness control. The impact of the deposition process and post-treatment condition on the MIM capacitor's breakdown voltage is studied and correlated with time of flight-secondary ion mass spectrometry (ToF-SIMS). Higher deposition temperature and thermal treatment of TiN and Al2O3 after deposition increase breakdown voltage and improve uniformity. ToF-SIMS demonstrates that Al2O3 higher deposition temperature or rapid thermal processing annealing reduce the diffusion of TiN in Al2O3 leading to thinner TiN/Al2O3 interface layers that influence breakdown voltage and uniformity

Electrocaloric temperature change in ferroelectric Si-doped hafnium oxide (HfO2) thin films: Presentation held at 37th Spring Meeting of the European Materials Research Society, E-MRS 2019, 27-31 May 2019, Nizza

Ferroelectric HfO2-based thin films receive extensive research interest due to their large spontaneous polarization, scalability, and CMOS compatible manufacturing. As in ferroelectrics, the remnant polarization exhibits a temperature dependence, one can observe a strong pyroelectric response in such films. Recently, the pyroelectric effect of doped HfO2 films has been observed [1]. The electrocaloric effect is closely related to it, as describing a temperature change of the material due to the application of an electric field. First published results indicate rather large electrocaloric coefficients, making doped HfO2 a promising candidate for on-chip solid-state cooling [2]. In this work, a specialized test structure is used to directly assess the strength of the electrocaloric effect in a 20 nm Si-doped HfO2 nano-laminate. A thin-film temperature sensor is formed on the metal-ferroelectric-metal structure, enabling excitation frequencies of up to 60 kHz. Measurement with respect to an electric bias field provides insight into the nature of thermal-electric energy conversion in HfO2 thin films. Additionally, bias dependent pyroelectric measurements are employed to assess the role of defect dipoles, which may have important implications for electrocaloric applications