Editors' Choice—Si- and Sn-Doped Homoepitaxial β-Ga2O3 Layers Grown by MOVPE on (010)-Oriented Substrates. (1st January 2017)

• Record Type: Journal Article
• Authors: Baldini, Michele; Albrecht, Martin; Fiedler, Andreas; Irmscher, Klaus; Schewski, Robert; Wagner, Günter
• Is Part Of: ECS journal of solid state science and technology. Volume 6:Number 2(2017)
• Page Start: Q3040
• Page End: Q3044
• Publication Date: 2017-01-01
• Subjects: gallium oxide -- MOCVD -- MOVPE -- thin layers -- transparent semiconductor oxides; Solid state chemistry -- Periodicals; Electronics -- Materials -- Periodicals; Electrochemistry -- Periodicals; 541.0421
• DOI: 10.1149/2.0081702jss
• Languages: English
• ISSNs: 2162-8777

Abstract

Abstract : We studied the growth of Si- and Sn-doped homoepitaxial β-Ga2 O3 layers on (010)-oriented substrates by metal organic vapor phase epitaxy (MOVPE). At optimal growth conditions (850°C, 5 mbar) the layers were smooth with RMS roughness values of ∼600 pm. A microstructural study by transmission electron microscopy (TEM) revealed a very high crystalline perfection of the layers. No dislocations or planar defects were observed within the field of view of TEM. Using Si as dopant, the free electron concentration could be varied in a range between 1 × 10 17 and 8 × 10 19 cm −3, while with Sn the doping range was restricted to 4 × 10 17 −1 × 10 19 cm −3 . This was explained by a pronounced Sn memory effect in the MOVPE reactor that hampers achieving low carrier densities and by incorporation issues that limit the doping efficiency at high Sn doping levels. The electron mobility for a given doping density increased from ∼50 cm 2 /Vs for n = 8 × 10 19 cm −3 to ∼130 cm 2 /Vs for n = 1 × 10 17 cm −3 independently of the dopant. These values match the best literature data relative to β-Ga2 O3 bulk crystals and layers grown by molecular beam epitaxy, setting a new standard for MOVPE-grown layers.