A Novel Bondpad report process for III–V semiconductor devices using full HSQ properties

This paper reports on an easy and quick planarization and passivation technique of III–V compound semiconductor compatible with nanoscale devices. Vertical etching requires good sidewalls passivation to reduce drastically the leakage current and to obtain a good planarization of the devices for metal connection. This novel technique offers the capability to planarize all the different compounds in the entire wafer independently of the height of the structure to be connected. This method uses the HSQ properties (fluidity, solidification to silica film by using O2 plasma treatment, negative tone e-beam lithography resist, low-k dielectric, etc.) to planarize and to passivate all the devices at once. We applied this quick and easy method to InP digital optical switches. We demonstrated photonic switches with high yield (>90%), high breakdown voltage (>30 V), low ohmic contact resistance (8 Ω) and a low leakage current (21 pA/μm2 for 5 V reversed bias).