Half-bridge silicon strain gauges are widely used in the fabrication of diaphragm-type high-pressure sensors, but in some applications, they suffer from low output sensitivity because of mounting position constraints. Through a special design and fabrication approach, a new half-bridge silicon strain gauge comprising one arc gauge responding to tangential strain and another linear gauge measuring radial strain was developed using Silicon-on-Glass (SiOG) substrate technology. The tangential gauge consists of grid patterns, such as the reciprocating arc of silicon piezoresistors on a thin glass substrate. When two half-bridges are connected to form a full bridge with arc-shaped gauges that respond to tangential strain, they have the advantage of providing much higher output sensitivity than a conventional half-bridge. Pressure sensors tested under pressure ranging from 0 to 50 bar at five different temperatures indicate a linear output with a typical sensitivity of approximately 16 mV/V/bar, a maximum zero shift of 0.05% FS, and a span shift of 0.03% FS. The higher output level of pressure sensing gauges will provide greater signal strength, thus maintaining a better signal-to-noise ratio than conventional pressure sensors. The offset and span shift curves are quite linear across the operating temperature range, giving the end user the advantage of using very simple algorithms for temperature compensation of offset and span shift.

Titanicone, obtained through molecular layer deposition (MLD) using TiCl4 and ethylene glycol (EG), is often regarded as a thin film of titanium ethylene glycolate [Ti(OCH2CH2O)2]. Nevertheless, titanicone exhibits a distinct vulnerability to moisture, while single crystals of Ti(OCH2CH2O)2 remain stable, even in the presence of water. To elucidate the origin of instability, we investigated the pathway of chemical degradation for titanicone using in situ and ex situ analytical methods such as Fourier transform infrared spectrometry, quartz crystal microbalance, quadrupole mass spectrometry, and X-ray photoelectron spectroscopy. Our analyses unveiled that the instability of the MLD-grown titanicone film in the presence of water can be primarily attributed to the high chlorine content present as Ti–Cl species and the coexistence of single-reacted EG species as well as double-reacted EG species, unlike in Ti(OCH2CH2O)2 crystals. Water molecules react with the Ti–Cl species, leading to the formation of Ti–OH species and the release of HCl gas. Furthermore, the single-reacted EG species undergo an intramolecular cyclization reaction catalyzed by HCl, resulting in the formation of Ti–OH and the liberation of ethylene oxide. Consequently, when exposed to water, the MLD-grown titanicone turns into a water-stable mixed film composed of TiO2 and Ti(OCH2CH2O)2.