Effect of surface nitridation on the epitaxial growth of few-layer sp2 BN
Effect of surface nitridation on the epitaxial growth of few-layer sp2 BN
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DOI：
10.1016/j.jcrysgro.2015.11.030
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发表时间：
2016-02-15
影响因子：
1.8
通讯作者：
Kiefer, Arnold
中科院分区：
文献类型：
--
作者：
Snure, Michael;Paduano, Qing;Kiefer, Arnold
氮化硼是一种很有前途的2D电介质材料，可用于许多电子应用。为了实现这种潜力，需要一种在微电子兼容基板上生产原子级薄层的方法。在本文中，我们描述了一种方法，外延生长少层sp（2）BN直接在绝缘衬底上，使用金属有机化学气相沉积（MOCVD）。我们还阐明了蓝宝石表面氮化对生长特性的影响。我们比较了氮化对生长速率、表面形貌和结构的影响，在很宽的V/III比范围内。根据V/III比，确定了两种不同的生长模式：在低V/III 3D岛生长是占主导地位的，在高V/III的生长过渡到自终止模式。在自终止生长下，通常实现1.5nm的膜厚度。表面氮化被发现，以提高成核，促进自终止生长，并导致原子级光滑的薄膜。反射高能电子衍射（RHEED）图谱显示BN和蓝宝石之间的外延关系为[1-100]平行于[11-201]和[0001]平行于[0001]。生长在低V/III比没有表面氮化产生的膜与大的六边形孔，这不能完全填充通过延长生长时间。通过表面氮化，这些孔被消除，产生连续光滑的薄膜。由爱思唯尔公司出版
Boron Nitride is a promising 2D dielectric material for use in numerous electronic applications. In order to realize this potential, a process for producing atomically thin layers on microelectronics-compatible substrates is desirable. In this paper we describe an approach to epitaxially grow few-layer sp(2) BN directly on an insulating substrate, using metal-organic chemical vapor deposition (MOCVD). We also elucidate the effect of sapphire surface nitridation on the growth characteristics. We compare the effect of nitridation on the growth rate, surface morphology and structure across a wide range of V/III ratios. Depending on the V/III ratio, two different growth modes were identified: at low V/III 3D island growth is dominant and at high V/III the growth transitions to a self-terminating mode. Under self-terminating growth a film thickness of 1.5 nm is typically achieved. Surface nitridation was found to improve nucleation, promoting self-terminating growth, and resulting in atomically smooth films. Reflection high energy electron diffraction (RHEED) patterns reveal the epitaxial relationship between BN and sapphire to be [1-100]parallel to[11-201 and [0001]parallel to[0001]. Growth at low V/III ratios without surface nitridation produced films with large hexagonal holes, which could not be completely filled by extending the growth time. Through surface nitridation, these holes were eliminated, producing continuous smooth films. Published by Elsevier B.V.