少层氮化硼的生长机理及技术研究

Mechanism and Technique Studies on Few-layer Boron Nitride Growth

采用MOCVD技术在50.8 mm(2英寸)蓝宝石衬底上开展氮化硼(BN)材料的外延生长研究。基于Ⅴ/Ⅲ族源的同时输运工艺,探究了无序岛状、生长自终止及二维层状等三种BN生长模式的外延机理,并实现了5-6层原子厚的二维BN材料的制备。同时,提出了一种Ⅴ/Ⅲ族源的同时输运及分时输运相结合的外延生长工艺,显著提升了二维BN材料质量,其中1μm×1μm表面粗糙度Ra为0.10 nm,光学带隙宽度为5.77 eV,拉曼E2g模式的半高宽为60.7 cm^(-1)。

A study of epitaxy growth of boron nitride(BN)was performed on 2-inch sapphire substrates by metal organic chemical vapor deposition(MOCVD).Based on the procedure of simultaneous supply ofⅤ/Ⅲsources,the growth mechanisms of BN which include disordered-island,self-terminating and two-dimensional(2D)layer-by-layer growth modes are discussed,presenting a visualized way to achieving few-layer BN material with only 5-6 layers.In addition,the procedure with a combination of simultaneous supply and alternative supply ofⅤ/Ⅲsources is also applied to BN epitaxy growth,which remarkably improves the crystal quality of the few-layer BN material,giving the surface roughness value Raclose to 0.10 nm in 1μm×1μm scans,optical band gap with 5.77eV and full width at half maximum(FWHM)of BN E2gmode equal to 60.7 cm^(-1).