CMOS-Compatible Wearable Sensors Fabricated Using Controlled Spalling

Wearable sensors can provide important human physiology and activity data and therefore have promising applications in healthcare, entertainment, and security. Here, we report the design, fabrication, and characterizations of a thin silicon film sensor for wearable sensor applications. Temperature, light, and strain sensing capabilities of the thin film of doped silicon, fabricated using a controlled spalling process, were fully characterized. An n-doped silicon thin-film sensor prepared with the spalling technology exhibited a temperature coefficient of −0.44%/°C. The sensor also showed excellent light sensing response in an illumination range from 110 to 1710 cd/mm
²
. The ratio of the electrical resistance changes over the applied forces was measured to be around 0.6%/N.