On-Chip Direct Laser Writing of Spectral Filter Structures for Terahertz Field-Effect Transistors

We demonstrate first results of 3D direct laser writing (DLW) of metallic filter structures on narrow-band antenna-coupled field-effect transistors (TeraFET) directly on the detector chip. The chip itself contains a spectroscopic line array of resonant TeraFETs ranging from 0.53 to 1.98 THz. We apply a 3D laser metal writing (DLW) process directly on the die, printing filter structures made of silver particles for the narrowing of the frequency response and the suppression of spurious waves. In our first measurements, we investigate changes in the detection resonance frequency in comparison to bare TeraFET arrays from the chip foundry.