Hydrogen gas sensing properties of Pt/Ta2O5 Schottky diodes based on Si and SiC substrates

Abstract

In this paper, we fabricated Pt/tantalum oxide (Ta 2 O 5 ) Schottky diodes for hydrogen sensing applications. Thin (4 nm) layer of Ta 2 O 5 was deposited on silicon (Si) and silicon carbide (SiC) substrates by radio frequency (RF) sputtering technique. We compared the performance of these sensors at different elevated temperatures of 100°C and 150°C. At these temperatures, the sensor based on SiC exhibited a larger sensitivity while the sensor based on Si exhibited a faster response toward hydrogen gas. We discussed herein, the responses exhibited by the Pt/Ta 2 O 5 based Schottky diodes demonstrated a promising potential for hydrogen sensing applications.

MOSFE-Capacitor Silicon Carbide-Based Hydrogen Gas Sensors

“…The operating temperature of 50–150 °C, which is typical for MOSFEC Si-based sensors, gives a response speed of 5–10 min when detecting hydrogen concentrations at the units-hundreds of ppm level. This corresponds to other authors’ results for different types of hydrogen sensors [ 13 , 20 , 21 ]. Such indicators are not always acceptable for safety tasks in conditions where there is a risk of harmful and dangerous gases’ rapid formation and accumulation.…”

“…For example, at an operating temperature of 150 °C, the characteristic response times to 1250 ppm Hydrogen for Si samples were about τ 0.9 = 2 min and τ 0.1 = 6 min, and for SiC samples, they were τ 0.9 = 5 min and τ 0.1 = 13 min. Comparing our results ( Figure 3 , Table 1 ) with [ 21 ], we see that the response times of the Schottky diodes with a Pt contact are comparable to SiC Sample No. 2 with the Pt electrode, while our sensors with the Pd electrode (both Si-based and SiC-based) at 200 °C have a response time of 30 to 70 s.…”

“…Since the idea of upgrading field-effect gas sensors by using WBG semiconductors is not new, it is interesting to compare our results with other authors’ data. Thus, in [ 21 ], using the example of hydrogen sensors based on Schottky diodes and Pt/Ta 2 O 5 structures deposited on different Si and SiC substrates by radio frequency (RF) sputtering, a comparison of the sensors’ operating parameters at temperatures from 25 °C to 200 °C was undertaken. The authors tested samples for exposure to H 2 with a concentration in the range from 600 ppm to 1% vol.…”

Highly Fast Response of Pd/Ta2O5/SiC and Pd/Ta2O5/Si Schottky Diode-Based Hydrogen Sensors

“…The results indicate an optimum operating temperature of 300 • C and, under this optimum condition, the Ta 2 O 5 /SiC-based sensor performs exceptionally well, showing excellent sensitivity along with fast rise and fall times of 7 s and 18 s, respectively. These results are significantly better than those previously reported for H 2 sensors [35,36] and suggest that the Pd/Ta 2 O 5 /SiC-based Schottky diode is a promising candidate for H 2 sensing applications. To the best of the present authors' knowledge, few reports on a Pd/Ta 2 O 5 /SiCbased Schottky diode aimed specifically at H 2 gas sensing have been published [37][38][39].…”