Manipulating Etch Selectivities in XeF₂ Vapour Etching

The vapour etching of silicon sacrificial layers is often a critical process in the fabrication micro/nanosystems. This method has number attractive features, particular, high etch rates and good selectivities associated with photoresist, SiO 2 , stoichiometric Si xmlns:xlink="http://www.w3.org/1999/xlink">3 N xmlns:xlink="http://www.w3.org/1999/xlink">4 regularly used metal films. However, materials that are commonly inert to XeF etched when located proximity layer. common situation such systems can become issue affecting control device reliability. work uses test structures have been designed be very sensitive, thereby delivering much lower then typically reported literature. sensitive quantification effect evaluate methods improve selectivity. suggests reduction processing temperature from 25°C 10°C increases Si: PECVD SiN selectivity by 68%. more easily implemented modification flow hydrogen into reaction chamber. improves an order magnitude LPCVD between 200% 600%.