Integrated atomic force microscopy array probe with metal-oxide-semiconductor field effect transistor stress sensor, thermal bimorph actuator, and on-chip complementary metal-oxide-semiconductor electronics

A microfabricated 2x1 array of active and self-detecting cantilevers is pre sented for applications in atomic force microscopy (AFM). The integrated de flection sensor is based on a stress sensing metal-oxide-semiconductor tran sistor. Full custom complementary metal-oxide-semiconductor amplifiers for signal readout are combined on the same chip. A sensor sensitivity of 2.25 mV/nm, or a change in current Delta Id/Id = 2.8 x 10(-6)/nm, was obtained a t the final output stage. Three Al-Si thermal bimorph actuators are integra ted on each cantilever for self-excitation and feedback actuation. The effi ciencies of the heaters are 2.4-4.7 K/mW. In the experimental setup, a maxi mum displacement of 8 mum was achieved at 45 mW input. A pair of parallel A FM images in the constant height mode, a typical tapping mode image, and a constant force image with 1.3 mum high features have been successfully take n with the array probe. (C) 2000 American Vacuum Society. [S0733-211X(00)18 806-7].