一种新型STM纳米计量仪

Novel Design of Nanometer Metrology-STM

阿贝(Abbe)误差作为纳米计量中的主要误差之一限制着测量精度的提高,故提出了一种新型STM纳米计量仪器,采用3个微型激光干涉仪与STM联用.微型激光干涉仪用来测量探针相对于样品在3个方向上空间位移.与其它STM纳米计量仪器相比,该仪器扫描部分放弃了传统管式扫描器和三角架扫描器,将扫描分为Z向和X Y平面扫描两部分,Z向扫描由独立的PZT驱动,X Y扫描由两个PZT驱动的柔性平行四杆导轨完成.这种设计理论上能使Z方向上Abbe误差完全消除,X Y方向上Abbe臂缩小到扫描范围的一半,最大50μm,使Abbe误差减小至可忽略的程度.微型激光干涉仪的使用还消除了扫描器PZT的非线性、滞后、爬行和老化等误差.

Abbe error is a main obstacle for achieving several nanometer uncertainties in scanning tunneling microscope (STM) instruments. This paper proposes a new STM design, in which the traditional tube scanner and tripod scanner are replaced by separated Z scanning and X-Y scanning, and three interferometers are used to measure X, Y, and Z displacements between the sample and tip. Z scanning is conducted by a single tube scanner, and the flexible parallel four-bar mechanism is employed for X-Y scanning. Theoretically, this design eliminates the Abbe error in Z direction and the Abbe offsets in X and Y direction are reduced to half of the scanning range, maximally about 50 μm, so the Abbe errors in X and Y direction can be negligible. In addition, the use of interferometers eliminates the errors caused by the non-linearity, hysteresis, creeping and aging of PZT material.