Verification of on-wafer photoconductive sampling for millimeter wave device characterization

Abstract

The development of ultrafast short pulse laser and photoconductive material makes it possible to generate an electrical pulse with a few picoseconds. In addition, with the photoconductive sampling, it is possible to measure the generated electrical short pulse with sub picosecond resolution. In this paper, as reducing the width of the generated electrical pulse, the photoconductive sampling applies for a new millimeter wave measurement technique to surpass the frequency limitation of the extant conventional electrical network analyzer due to the discontinuities of connectors and the lack of millimeter wave sources. To verify the reliability of on-wafer photoconductive sampling as a new measurement technique at millimeter wave region, simple millimeter wave devices with simple coplanar waveguide structure are measured using on-wafer photoconductive sampling. In addition, to confirm the measurement results, these results are compared with current models, FDTD (Finite Difference Time Domain) in time domain, and the commercial software in frequency domain.