Advances of SiC-based MOS capacitor hydrogen sensors for harsh environment applications

Enhancement of the Stability of Ti and Ni Ohmic Contacts to 4H-SiC with a Stable Protective Coating for Harsh Environment Applications

“…In the presence of moisture or impurities such as Na or Cl, oxidation dynamics in particular is largely enhanced. 3,4 Okojie et al reported outstanding results regarding the long-term stability of Ti contacts to 4H-SiC and 6H-SiC at high temperatures in air, achieving a figure of merit of 1000 h at 600°C. 5,6 In that work, a tantalum silicide (TaSi x ) layer was employed as a diffusion barrier between the Ti contact and the Pt top layer.…”

Pt-decorated GaN nanowires with significant improvement in H 2 gas-sensing performance at room temperature

“…Scientists and engineers alike are making efforts in the development and manufacturing of green and environmentally friendly products [1,2]. Among these products, H 2 sensors are considered very important in various applications in particular for safety reasons [3], such as detection of H 2 leakage below the lower explosive limit (LEL) of 4 % by volume ratio of H 2 to air [4]. By nature, H 2 is explosive [5].…”

“…If H 2 flows into the air from a tank or valve, it will pose serious hazard. Additionally, H 2 is a major cause of corrosion, which occurs when tiny H 2 atoms penetrate into steel and other metals resulting in the weakening of the internal structure (H 2 blistering or H 2 embrittlement), thus the mechanical properties of metals, for instance ductility, strength and fracture toughness, are seriously affected [4,6]. Also, it is important to know that H 2 when absorbed as low as 1 ppm can cause cracking [4], which becomes especially important for elevated temperature applications [7].…”

“…In addition, a broad detection range is also desirable [6,30], where the development of gas sensors for 10-1000 ppm of H 2 is of high interest [4]. For aerospace applications and automotive industries, H 2 sensors that can operate at high temperatures and under potentially corrosive conditions are very much required [31].…”

SiC-based MIS gas sensor for high water vapor environments

“…The first gas sensor based on MIS technology is attributed to Lundström et al [1], who in 1975 reported a hydrogen-sensitive Pd-MOS transistor fabricated on conventional silicon (Si) substrate. Later, the introduction of wide band-gap semiconductors, such as SiC, group-III nitrides (AlN, GaN and AlGaN) and diamond, made possible the increase of the operating temperature of the device above that of Si (limited to below 250 • C) [2][3][4][5]. The higher operating temperature allows the devices to work nearer the source of the hazardous gases, which are usually produced in high temperature conditions.…”