Displacement Talbot lithography for nano-engineering of III-nitride materials

Abstract

Nano-engineering III-nitride semiconductors offers a route to further control the optoelectronic properties, enabling novel functionalities and applications. Although a variety of lithography techniques are currently employed to nano-engineer these materials, the scalability and cost of the fabrication process can be an obstacle for large-scale manufacturing. In this paper, we report on the use of a fast, robust and flexible emerging patterning technique called Displacement Talbot lithography (DTL), to successfully nano-engineer III-nitride materials. DTL, along with its novel and unique combination with a lateral planar displacement (D2TL), allow the fabrication of a variety of periodic nanopatterns with a broad range of filling factors such as nanoholes, nanodots, nanorings and nanolines; all these features being achievable from one single mask. To illustrate the enormous possibilities opened by DTL/D2TL, dielectric and metal masks with a number of nanopatterns have been generated, allowing for the selective area growth of InGaN/GaN core-shell nanorods, the top-down plasma etching of III-nitride nanostructures, the top-down sublimation of GaN nanostructures, the hybrid top-down/bottom-up growth of AlN nanorods and GaN nanotubes, and the fabrication of nanopatterned sapphire substrates for AlN growth. Compared with their planar counterparts, these 3D nanostructures enable the reduction or filtering of structural defects and/or the enhancement of the light extraction, therefore improving the efficiency of the final device. These results, achieved on a wafer scale via DTL and upscalable to larger surfaces, have the potential to unlock the manufacturing of nano-engineered III-nitride materials.

Influence of the reactor environment on the selective area thermal etching of GaN nanohole arrays

“…Optimized thermal etching parameters were then used for further experiments on various mask configurations created on c-plane and (1122) semi-polar GaN templates. A detailed description of the dielectric mask fabrication process can be found in the Methods section and our previous publication 33 , while SEM images of the SiN x openings are shown in Fig. S1.…”

“…However, the process was reported to be strongly sensitive to threading defects, resulting in the formation of pores under the mask and, therefore, with a poor organization of nanoholes overall and poor uniformity of the nanohole dimensions. More recently, Damilano and co-authors reported several works on the selective area sublimation (SAS) of nanorods and nanoholes having a straight sidewall profile, achieved in a molecular beam epitaxy (MBE) chamber either from a SiN x self-organized mask 15,31 , or a SiN x nanopatterned mask 32,33 . With their conditions, nanorods and nanoholes with a high organization and fairly uniform dimensions were successfully achieved 32,33 .…”

“…More recently, Damilano and co-authors reported several works on the selective area sublimation (SAS) of nanorods and nanoholes having a straight sidewall profile, achieved in a molecular beam epitaxy (MBE) chamber either from a SiN x self-organized mask 15,31 , or a SiN x nanopatterned mask 32,33 . With their conditions, nanorods and nanoholes with a high organization and fairly uniform dimensions were successfully achieved 32,33 . Despite the successful formation of nanoholes, few technical details have been provided on the impact of the thermal etching environment on the morphology of the nanohole arrays.…”

Strain-induced yellow to blue emission tailoring of axial InGaN/GaN quantum wells in GaN nanorods synthesized by nanoimprint lithography

“…Furthermore, a metal mask is preferred to obtain high aspect ratio structures by deep plasma etching. While displacement talbot lithography can pattern thick resist at the nanoscale 30 , it is still an emerging technique with a resolution limited by the wavelength illumination source, often 365 nm 30 or 266 nm 31 , while NIL resolution can be scaled further down.…”

Diamond diffractive optics—recent progress and perspectives

“…2.5D structures can be created using 2-photon lithography [40]. For diffractive structures, special techniques can prove successful, such as interference lithography [45] and Talbot lithography [46], which are uniquely suited to produce periodic structures.…”