PZT cantilever array integrated with piezoresistor sensor for high speed parallel operation of AFM

In this research, the self-actuating high quality PZT cantilever with a piezoresistor was fabricated, and characterized for high speed AFM. The parasitic parameters inducing the electrical coupling between sensor and PZT actuator, was studied using simple equivalent circuit model of AFM cantilever. As a result of simulation, a new design was proposed to minimize the coupling capacitance between sensor and actuator by modifying the previous structure of cantilever described in [Appl. Phys. Lett. 72 (1998) 2340]. The fabricated PZT cantilever provided high tip displacement of 0.55 mum/V, has low leakage current, and enabled low voltage operation of AFM system. The optimized design at self-actuating PZT cantilever with a piezoresistor shows five times lower coupling voltage than the current cantilever structure shown in [Appl. Phys. Lett. 72 (1998) 2340]. The measured resonant frequency was 73 kHz which was 100 times higher than that of conventional piezotube scanner. The piezotube scanner shows creep phenomena at scan speed of 180 mum/s scan speed, but the fabricated self-actuating PZT cantilever has a good scanned image even at I mm/s. Moreover, an array of 25 PZT cantilevers with piezoresistor that are spaced by 100 gm for parallel operation, was fabricated successfully. (C) 2003 Elsevier Science B.V. All rights reserved.