Intense thermal shock generators made of micron-thick SnO2 layers for the on-chip rapid thermal processing in air

Abstract

Thermal shock-resistant heaters are essential in various electronic devices, including chemical sensors and pyroelectric electron emitters. The advent of ultrafast high-temperature sintering and shock synthesis of nanomaterials has increased the demand for air-operating high-rate joule heaters. Moreover, incorporating such heaters at the chip level would revolutionize current rapid thermal processing methods in semiconductor technology. Here, transparent micron-thick SnO2 resistors are grown by spray pyrolysis on alumina, silica, and oxidized silicon chips and used as thermal shock-resistant air-operating heaters. These heaters can generate repeated heating cycles at rates of 15,000 °C/s up to 900 °C/s. Tin is a group IV element and its impact on Si- and SiO2-based devices is minimal making the presented device silicon compatible. The superior performance of the presented heaters is attributed to the tin oxide’s unique combination of physicochemical properties including high-temperature chemical stability in oxidizing atmospheres, suitable intrinsic conductivity, and optimal negative temperature coefficient of resistance. The application of the SnO2 heaters for the rapid on-chip high-temperature oxidation and sintering of low-melting-point metal thin films, while preserving the metal layer’s nanotexture, is demonstrated.