LENGTH MEASUREMENT USING A REGULAR CRYSTALLINE LATTICE AND A DUAL TUNNELING UNIT SCANNING TUNNELING MICROSCOPE IN A THERMO-STABILIZED CELL

dThis paper describes length measurements using a regular crystalline lattice as a reference scale and a dual tunnelling unit scanning tunne lling microscope (DTU-STM) as a detector in a thermo-stabilized cell. Direct length comparisons between a certified standard scanning electr on microscope (SEM) grating with an average pitch of 240 nm and a high ly oriented pyrolytic graphite (HOPG) lattice spacing, which is 0.246 nm, were performed. Images of the grating and the HOPG were simultaneo usly obtained in the range of 1 mu m using the DTU-STM. The thermo-sta bilized cell was developed to suppress any thermal drift error. In ord er to shorten the measurement time and thus reduce the thermal drift e rror, lengths of 1 mu m for the two samples were measured along the fa st scanning axis. Rapid scanning, in which the tip speed was up to 1 m u m s(-1), was also utilized to shorten the measurement time. The grat ing pitch obtained by comparison with the HOPG lattice spacing agreed with that calibrated by the conventional diffraction method within an error of 2%.