Quick planarisation based on hydrogen silsesquioxane (HSQ) for deep etched InP based structures

The ability of HSQ resist films to planarise active deep etched (1.5-2 mum) InP based structures with electrodes is demonstrated for the first time. Vertically etched III-V semiconductor devices require planarisation of the passivation material for metal interconnections and device integration. A new and quicker method is presented for which it is not necessary to use mask opening on the top of the devices to define via patterns. A comparison between conventional silicon dioxide (SiO₂) planarisation and the demonstrated HSQ method validates the interest of the latter.