GAAS ALGAAS SELF-SENSING CANTILEVERS FOR LOW-TEMPERATURE SCANNING PROBE MICROSCOPY/

We have fabricated scanning probe microscope cantilevers with dimensio ns 65 x 11.4 x 0.25 mu m(3) and 3 x 2 x 0.129 mu m(3) from GaAs/Al0.3G a0.7As heterostructures containing two-dimensional electron gases. Def lection is measured by an integrated field-effect transistor (FET) tha t senses strain via the piezoelectric effect and provides a low noise, low power displacement readout. We present images of a 200 nm mice gr ating taken with the large cantilever having a deflection (force) nois e 10 Angstrom/(root)Hz (19 pN/(root)Hz) at T = 2.2 K. The small cantil ever has a resonant frequency of 11 MHz, a FET gate charge noise of 0. 001 e / (root)Hz, and is projected to have a deflection (force) noise of 0.002 Angstrom/(root)Hz (1 pN/(root)Hz) at T = 4.2 K. (C) 1998 Amer ican Institute of Physics. [S0003-6951(98)00734-7]