Fabrication of Integrated HBV Multipliers for THz Generation

Licentiate thesis, 2013

The main objective of this licentiate thesis is to demonstrate silicon integrated HBV frequency multipliers for THz generation with RF performance comparable with InP technology. The choice of silicon is motivated by better thermal and mechanical properties, cost and ease of integration compared to III-V semiconductor substrates. Moreover, micromachining of silicon allows fabrication of membranes, antennas and waveguides suitable for THz frequencies. A W-band silicon integrated frequency tripler is demonstrated. Plasma assisted wafer bonding was utilised to integrate InP-based HBV material on silicon substrate. The transferred material was characterised using: atomic force microscopy, transmission electron microscopy, X-ray diffractometry and Auger spectroscopy. The maximum output power measured for this device was more than 180 mW, corresponding to 23 % of efficiency. For comparison, a monolithically integrated HBV frequency multiplier on InP substrate was fabricated and demonstrated. The peak effiency and output power for both the Si and the InP basecid tripler are comparable. Finally, a x tuned 175 GHz frequency quintupler is presented. The multiplier is based on a single HBV diode that is flip-chip soldered into a microstrip matching circuit. The circuit is fabricated from AlN substrate, a material that has a good thermal conductivity. This device delivers 60 mW output power corresponding to 6.3 % of efficiency.