Integrating microfluidics with biosensors is of great research interest with the increasing trend of lab-on-the chip and point-of-care devices. Though there have been numerous studies performed relating microfluidics to the biosensing mechanisms, the study of the sensitivity variation due to microfluidic flow is very much limited. In this paper, the sensitivity of interdigitated electrodes was evaluated at the static drop condition and the microfluidic flow condition. In addition, this study demonstrates the use of gold nanoparticles to enhance the sensor signal response and provides experimental results of the capacitance difference during cancer antigen-125 (CA-125) antigen–antibody conjugation at multiple concentrations of CA-125 antigens. The experimental results also provide evidence of disease-specific detection of CA-125 antigen at multiple concentrations with the increase in capacitive signal response proportional to the concentration of the CA-125 antigens. The capacitive signal response of antigen–antibody conjugation on interdigitate electrodes has been enhanced by approximately 2.8 times (from 260.80 to 736.33 pF at 20 kHz frequency) in static drop condition and approximately 2.5 times (from 205.85 to 518.48 pF at 20 kHz frequency) in microfluidic flow condition with gold nanoparticle-coating. The capacitive signal response is observed to decrease at microfluidic flow condition at both plain interdigitated electrodes (from 260.80 to 205.85 pF at 20 kHz frequency) and gold nano particle coated interdigitated electrodes (from 736.33 to 518.48 pF at 20 kHz frequency), due to the strong shear effect compared to static drop condition. However, the microfluidic channel in the biosensor has the potential to increase the signal to noise ratio due to plasma separation from the whole blood and lead to the increase concentration of the biomarkers in the blood volume for sensing.

This work evaluates the defects in HfZrO as a function of Zr addition into HfO2 and when the dielectric was subjected to a slot-plane-antenna (SPA) plasma treatment in a cyclic process to form TiN/HfZrO/SiON/Si gate stacks. The defect energy levels, estimated by temperature-dependent current-voltage measurements, suggest that Zr addition in HfO2 modifies the charge state of the oxygen vacancy formation, V+. The influence of electron affinity variation of Hf and Zr ions on the charged oxygen vacancy levels seems to have contributed to the increase in defect activation energy, Ea, from 0.32 eV to 0.4 eV. The cyclic SPA plasma exposure further reduces the oxygen vacancy formation because of the film densification. When the dielectric was subjected to a constant voltage stress, the charge state oxygen vacancy formation changes to V2+ and improvement was eliminated. The trap assisted tunneling behavior, as observed by the stress induced leakage current characteristics, further supports the oxygen vacancy formation model.

This paper has demonstrated a high-quality HfO 2based gate stack by depositing atomic-layer-deposited HfAlO x along with HfO 2 in a layered structure. In order to get a multifold enhancement of the gate stack quality, both Al percentage and distribution were observed by varying the HfAlO x layer thickness and its location in the gate stack. It was found that < 2% Al/(Al + Hf)% incorporation can result in up to 18% reduction in the average EOT along with up to 41% reduction in the gate leakage current, as compared to the dielectric with no Al content. On the other hand, excess Al presence in the interfacial layer moderately increased the interface state density D it . When devices were stressed in the gate injection mode at a constant voltage stress, the dielectrics with Al/(Hf+Al)% < 2% showed resistance to stressinduced flatband voltage shift ΔV F B , and stress-induced leakage current. The time-dependent dielectric breakdown characteristics showed a higher charge to breakdown and an increase in the extracted Weibull slope β, which further confirms an enhanced dielectric reliability for devices with < 2% Al/(Al + Hf)%. Index Terms-Equivalent oxide thickness (EOT), HfAlO x , interface state density (D it ), stress-induced flatband voltage shift (ΔV F B ), stress-induced leakage current (SILC), time-dependent dielectric breakdown (TDDB).

This work investigates the interface state density, Dit by conductance method for two different processing conditions: (1) cyclic deposition and slot-plane-antenna (SPA) Ar plasma exposure, DSDS, and (2) cyclic deposition and annealing, DADA, during the deposition of ALD Hf1-xZrxO2 to fabricate the TiN/Hf1-xZrxO2/SiON/Si gate stack. The Zr percentage was varied in the dielectrics from x = 0 to 0.31 and 0.8 for DSDS processing and x = 0 to 0.8 for DADA processing. The control samples were deposited with standard atomic layer deposition (ALD) process (As-Dep) without any cyclic treatment. The addition of ZrO2 and SPA plasma exposure is found to suppress interface state generation. DSDS Hf1-xZrxO2 with x = 0.8 demonstrated superior equivalent oxide thickness downscaling and the lowest Dit. The electron affinity variation of Hf and Zr ion seems to contribute to reduced Dit generation after a constant voltage stress. On the other hand, DADA process increases the midgap Dit when Zr is added to HfO2. In addition, DADA processed dielectrics showed higher degradation when stressed because of increased trap assisted tunneling through charged grain boundaries. Furthermore, DSDS Hf1-xZrxO2 (x = 0.8) with two different interfacial layers: (1) UV nitridation of chemically grown SiO2 and (2) plasma oxynitride grown after removing the chemically grown SiO2 was investigated. The interface characteristics observed for SiON formed by UV nitridation seems to be better as compared to that formed by plasma oxynitride, which is attributed to the more uniform nitrogen incorporation by UV nitridation.

The reliability of atomic layer-deposited Hf0.2Zr0.8O2 and HfO2 on a SiON interfacial layer (IL) with cyclic deposition and annealing (DADA) and cyclic deposition and slot-plane-antenna Ar plasma exposure (DSDS) is studied. The results are compared with control, that is, As-Deposited samples, without any treatment during or after the dielectric deposition. DSDS Hf0.2Zr0.8O2 demonstrates a promising equivalent oxide thickness (EOT) downscaling ability, a reduced gate leakage current, and low mid-gap interface state density as compared to the control device, while DADA Hf0.2Zr0.8O2 has degraded the value of EOT as well as a degraded interface. When devices are subjected to a constant voltage stress in the gate injection mode, DSDS Hf0.2Zr0.8O2 showed a four times reduction in the flat-band voltage shift and a three order of magnitude reduction in the stress-induced leakage current within 100-s stress as compared to the control sample. The observed time to failure, T63%, is the highest for DSDS Hf0.2Zr0.8O2. The addition of Zr and the cyclic plasma exposure (DSDS process) seems to supress the oxide trap formation in Hf0.2Zr0.8O2 films. When DSDS Hf0.2Zr0.8O2 deposited on two different ILs, SiON and plasma oxynitride are compared, in that SiON demonstrates improved reliability as compared to plasma oxynitride.