A study of long term operation and reliability of heated atomic force microscope cantilevers

This paper presents a detailed investigation of the long term operation and reliability of heated atomic force microscope (AFM) cantilevers. The electrical and thermal operation of these heated AFM cantilevers depends upon the distribution of dopants within the silicon cantilever. Over long term operation, or for operation at very high temperatures, the cantilevers' electro-thermal properties can change due to dopant diffusion at the junction between the cantilever heater and the cantilever leg. We analyze this change in cantilever behavior at high heating temperatures, up to 1100 degrees C, and long heating times, up to 108 h. At extreme heating conditions, the cantilevers' electro-thermal properties change by as much as 24%, resulting in significant errors in cantilever calibration. The main failure mechanism of these heated AFM cantilevers is the melting of heater-leg junction at high cantilever temperatures, as high junction resistances induced the localized heating. Understanding and accounting for long term operational reliability is crucial for consistent and repeatable uses of heated cantilevers, especially for applications in material property measurements and nanomanufacturing.