scholarly journals Capacitance Electrochemical pH Sensor Based on Different Hafnium Dioxide (HfO2) Thicknesses

Chemosensors ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 13
Author(s):  
Zina Fredj ◽  
Abdoullatif Baraket ◽  
Mounir Ben Ali ◽  
Nadia Zine ◽  
Miguel Zabala ◽  
...  

Over the past years, to achieve better sensing performance, hafnium dioxide (HfO2) has been studied as an ion-sensitive layer. In this work, thin layers of hafnium dioxide (HfO2) were used as pH-sensitive membranes and were deposited by atomic layer deposition (ALD) process onto an electrolytic-insulating-semiconductor structure Al/Si/SiO2/HfO2 for the realization of a pH sensor. The thicknesses of the layer of the HfO2 studied in this work was 15, 19.5 and 39.9 nm. HfO2 thickness was controlled by ALD during the fabrication process. The sensitivity toward H+ was clearly higher when compared to other interfering ions such as potassium K+, lithium Li+, and sodium Na+ ions. Mott−Schottky and electrochemical impedance spectroscopy (EIS) analyses were used to characterise and to investigate the pH sensitivity. This was recorded by Mott–Schottky at 54.5, 51.1 and 49.2 mV/pH and by EIS at 5.86 p[H−1], 10.63 p[H−1], 12.72 p[H−1] for 15, 19.5 and 30 nm thickness of HfO2 ions sensitive layer, respectively. The developed pH sensor was highly sensitive and selective for H+ ions for the three thicknesses, 15, 19.5 and 39.9 nm, of HfO2-sensitive layer when compared to the other previously mentioned interferences. However, the pH sensor performances were better with 15 nm HfO2 thickness for the Mott–Schottky technique, whilst for EIS analyses, the pH sensors were more sensitive at 39.9 nm HfO2 thickness.

Crystals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 136 ◽  
Author(s):  
Zhigang Xiao ◽  
Kim Kisslinger ◽  
Sam Chance ◽  
Samuel Banks

We report the growth of nanoscale hafnium dioxide (HfO2) and zirconium dioxide (ZrO2) thin films using remote plasma-enhanced atomic layer deposition (PE-ALD), and the fabrication of complementary metal-oxide semiconductor (CMOS) integrated circuits using the HfO2 and ZrO2 thin films as the gate oxide. Tetrakis (dimethylamino) hafnium (Hf[N(CH3)2]4) and tetrakis (dimethylamino) zirconium (IV) (Zr[N(CH3)2]4) were used as the precursors, while O2 gas was used as the reactive gas. The PE-ALD-grown HfO2 and ZrO2 thin films were analyzed using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM). The XPS measurements show that the ZrO2 film has the atomic concentrations of 34% Zr, 2% C, and 64% O while the HfO2 film has the atomic concentrations of 29% Hf, 11% C, and 60% O. The HRTEM and XRD measurements show both HfO2 and ZrO2 films have polycrystalline structures. n-channel and p-channel metal-oxide semiconductor field-effect transistors (nFETs and pFETs), CMOS inverters, and CMOS ring oscillators were fabricated to test the quality of the HfO2 and ZrO2 thin films as the gate oxide. Current-voltage (IV) curves, transfer characteristics, and oscillation waveforms were measured from the fabricated transistors, inverters, and oscillators, respectively. The experimental results measured from the HfO2 and ZrO2 thin films were compared.


2017 ◽  
Vol 11 (7) ◽  
pp. 1700123 ◽  
Author(s):  
Markus H. Jakob ◽  
Sebastian Gutsch ◽  
Claire Chatelle ◽  
Abinaya Krishnaraja ◽  
John Fahlteich ◽  
...  

2011 ◽  
Vol 11 (05) ◽  
pp. 959-966 ◽  
Author(s):  
YI-TING LIN ◽  
YU-HONG YU ◽  
YU CHEN ◽  
GUO-JUN ZHANG ◽  
SHI-YANG ZHU ◽  
...  

Vertical silicon nanowire (SiNW) platforms are candidates for use in ultrasensitive biosensors, with surface-to-volume ratio higher than one-dimensional SiNW . In this paper, a vertical SiNW electrolyte–insulator–semiconductor (EIS) structure with an ALD-HfO2 sensing membrane is proposed for use in a hydrogen ion sensor. Hafnium dioxide is used as the sensing membrane, which was deposited on the surface of the vertical SiNW structure by atomic layer deposition. The sensing properties were examined using a HP4284A high-precision LCR analyzer. A linear relationship was found between the flatband voltage shift and the hydrogen ion concentration. Comparing with different diameters of SiNW , the sensitivity with diameter of 200 nm was slightly higher than 100 nm. A post-deposition rapid thermal annealing (RTA) was utilized to optimize the sensing properties, and the sensitivity was increased to 51.07 mV/pH.


2019 ◽  
Vol 3 (15) ◽  
pp. 279-282 ◽  
Author(s):  
Byung Soo So ◽  
Wontae Cho ◽  
Yil-Hwan You ◽  
Jin-Ha Hwang ◽  
Sun Sook Lee ◽  
...  

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Guilin Yin ◽  
Shiheng Bai ◽  
Xinglong Tu ◽  
Zheng Li ◽  
Yanpeng Zhang ◽  
...  

2020 ◽  
Vol 709 ◽  
pp. 138191
Author(s):  
R. Pietruszka ◽  
B.S. Witkowski ◽  
S. Zimowski ◽  
T. Stapinski ◽  
M. Godlewski

Sign in / Sign up

Export Citation Format

Share Document