Laser-Diode Based Scanning Force Microscope and Ultrafast Sampling Probe

Abstract

New discoveries in fabrication technology and in device physics have open the way for a class of electronic and optoelectronic devices with nanometer-scale dimensions. These devices offer the opportunity to work with electrons confined to 2-D, 1-D and 0-D in space. In an effort to understand how individual devices work it will be necessary to interrogate individual submicron structures. Aside from the fine dimensions of the contacts used for such measurements it will be necessary to make measurement with very low invasiveness and increasingly, with higher speed. To meet the challenges of new nano-technologies we have developed a probe which demonstrates high impedance voltage measurement using a 0.1-micron contacting tip. The voltage of the tip is photoconductively sampled allowing waveforms to be measured with picosecond resolution [1]. In this paper we describe the operation of the probe using a gain switched laser diode to make measurements which extract only a few fC from the device under test. We also show the probes value as a high-speed, high sensitivity probe for millimeter-wave circuits.