石墨表面扫描隧道显微镜纳米级加工研究

Study on the Nanolithography of Graphite Surface Using Scanning Tunneling Microscope

利用自制的扫描隧道显微镜 (STM ) ,进行了石墨表面的纳米级加工研究。在用STM对固体材料表面进行纳米级超微加工过程中 ,当探针 -试样间施加一高电压脉冲时 ,电子反馈回路将使探针急速回缩 ,导致实际有效电压脉冲宽度远小于所施加的电压脉冲宽度。我们专门设计了由计算机编程控制的瞬时“保持”功能 ,即在高电压脉冲作用过程中 ,使探针始终固定在原有位置 ,并保持原有探针 -试样间距不变。因而在进行固体材料表面纳米级超微加工时 ,可准确地测得有效电压脉冲宽度。通过在大气中对石墨表面的蚀刻研究 ,首次测得在电压脉冲幅值为 4V时 ,有效脉宽阈值为 ( 0 .0 4± 0 .0 1 ) μs。

Our home made scanning tunneling microscope(STM) is utilized to study the nanolithography of graphite surface.When it is employed in nanolithography on solid material surfaces,due to the intrinsic feedback response,the tip would always draw back swiftly as the high voltage pulse is applied across the tip and the sample.This makes it difficult to exactly determine the real acting time.This STM system has software controlled lithography functions.It can temporarily cut off the feedback loop and hold the tip sample distance constantly during the high voltage pulse acting period.Thus,the effective pulse width could precisely be measured in nanolithography of the solid material's surface.Through the study on the graphite surface lithography in air the threshold of the effective pulse width is first measured to be(0.04±0.01)μs under the pulse amplitude of 4V.