Revealing inhomogeneous Si incorporation into GaN at the nanometer scale by electrochemical etching. Issue 10 (4th March 2020)

• Record Type: Journal Article
• Authors: Sawicka, Marta; Fiuczek, Natalia; Turski, Henryk; Muziol, Grzegorz; Siekacz, Marcin; Nowakowski-Szkudlarek, Krzesimir; Feduniewicz-Żmuda, Anna; Wolny, Paweł; Skierbiszewski, Czesław
• Is Part Of: Nanoscale. Volume 12:Issue 10(2020)
• Page Start: 6137
• Page End: 6143
• Publication Date: 2020-03-04
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/c9nr10968d
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : Step-bunching during epitaxy induces inhomogeneous incorporation of a Si dopant into GaN at the nanometer scale as revealed by electrochemical etching. Abstract : Typical methods of doping quantification are based on spectroscopy or conductivity measurements. The spatial dopant distribution assessment with nanometer-scale precision is limited usually to one or two dimensions. Here we demonstrate an approach to detect three-dimensional dopant homogeneity in GaN:Si layers using electrochemical etching (ECE). GaN:Si layers are grown by plasma-assisted molecular beam epitaxy. Dopant incorporation is uniform when the growth front morphology is atomically flat. Non-uniform Si incorporation into GaN is observed when step-bunches are present on the surface during epitaxy. In this study we show that local Si concentration in the area of step-bunch is about three times higher than in the area between step-bunches. ECE spatial resolution in our experiment is estimated to be about 50 nm. This makes ECE a simple and quantitative probing tool for local three-dimensional conductivity homogeneity assessment. Our study proves that ECE could be important both for fundamental studies of crystal growth physics and impurity incorporation and for ion-implanted structures and post-processing device control.