Suresh Sundaram(1),(2),(3)*,  Soufiane Karrakchou(1),(2), Adama Mballo(2), Phuong Vuong(2), Yacine Halfaya(2), Gilles Patriarche(4), Tarik Moudakir(5), Paul L. Voss(1),(2), Jean Paul Salvestrini(1),(2),(3), Abdallah Ougazzaden(1),(2).

 

(1)Georgia Institute of Technology, School of Electrical and Computer Engineering, GT-Lorraine, 57070 Metz, France.

(2)CNRS, IRL 2958, GT- CNRS, 2 rue Marconi, 57070 Metz, France.

(3) GT Lorraine, 2 rue Marconi, 57070 Metz, France.

(4) Centre de Nanosciences et de Nanotechnologies, Universite Paris-Saclay, C2N–Site de Marcoussis, Route de Nozay, F-91460 Marcoussis, France

(5) Institut Lafayette, 2 rue Marconi, 57070 Metz, France

 

Here, We review the MOVPE growth of highly oriented high quality layered h-BN on sapphire substrates while turbostratic BN grows on dielectric (SiO2 and SiN) patterns on the substrate. We find that the turbostratic BN on the dielectric patterns inhibits further growth of GaN. This phenomenon results in selective area growth of GaN based isolated device structures only on highly oriented h-BN.

     To understand this new kind of selective area growth on 2D materials, 20 nm thick h-BN layers were grown separately on dielectric patterned sapphire substrates. On sapphire, the h-BN formed semi-hexagonal wrinkles which is evidence of growth of high quality 2D h-BN. Localized SIMS measurements confirmed the presence of BN on dielectric SiO2.  Additional cross sectional TEM studies confirm that the h-BN on the sapphire substrates is highly oriented and layered whereas the BN on the dielectric patterns are nanocrystalline and randomly alligned. This study confirmed that the highly oriented, layered h-BN preferentially grows only on single crystalline and highly oriented substrates.

     Furthermore, GaN based LED structure growth on these patterning induced quality controlled BN templates resulted in localized selective area growth. Homogeneous, single crystalline GaN based device structure growth occured only in regions where layered h-BN is deposited, avoiding randomly-oriented BN on SiO2. SEM and cathodoluminescence studies confirmed that the dielectric patterns isolated GaN regions from each other. We conclude from further structural and optical charcaterisations that the preferential growth of  oriented h-BN controls the selectivity of III-Nitride device structures. This SAG approach also results in high quality device strucures and avoids self delamination occuring during the growth. This study also allows localized device liftoff and transfer, opening up heterogeneous integration possibilities needed for realization of novel device architectures and device isolation/passivation.

 

                              
Presenting author Email address: suresh.sundaram@ece.gatech.edu