Selective Area Epitaxy of GaN Stripes With Sub-200 nm Periodicity

We present growth studies on gallium nitride (GaN) stripes with {101̄1} side facets grown on c-oriented GaN templates on sapphire. Via plasma enhanced chemical vapor deposition (PECVD), a 20 nm thick SiO2 mask is deposited on top of the templates. Afterwards, a polymethylmethacrylate (PMMA) based resist is patterned with stripes oriented along the GaN a-direction by electron beam (e-beam) lithography. The stripes have a periodicity below 200 nm. The pattern is transferred via fluorine based dry-etching with an inductively coupled plasma (ICP) reactive ion etching (RIE) process. Any remaining resist is removed with oxygen plasma and the samples are cleaned before epitaxy. The influence of e-beam parameters, etching rates, etching agents and etching times on the pattern transfer and subsequent overgrowth is investigated. Semipolar InGaN/GaN quantum wells are deposited on the side facets of the nanostripes.