Improved Ti-mask selective-area growth (SAG) by rf-plasma-assisted molecular beam epitaxy demonstrating extremely uniform GaN nanocolumn arrays
Improved Ti-mask selective-area growth (SAG) by rf-plasma-assisted molecular beam epitaxy demonstrating extremely uniform GaN nanocolumn arrays
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DOI：
10.1016/j.jcrysgro.2008.11.056
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发表时间：
2009-03-15
影响因子：
1.8
通讯作者：
Kikuchi, Akihiko
中科院分区：
文献类型：
--
作者：
Kishino, Katsumi;Sekiguchia, Hiroto;Kikuchi, Akihiko
GaN纳米柱的Ti掩模选择性区域生长（SAG）在900 ℃的生长温度下进行，同时将供应的氮气流速（Q（N2））从3.5减小到0.5sccm。展示了GaN纳米柱的高度均匀的阵列。在低Q（N2）下，加速了Ga从氮化Ti掩模上的脱附和扩散，这充分抑制了Ti掩模表面上的晶体成核，因此即使当纳米柱之间的间距为几百nm时，也实现了GaN纳米柱的SAG。随着Q（N2）的降低，Ga解吸的增强导致GaN纳米柱的生长速率从1.05 μ m/h降低到0.15 μ m/h。GaN纳米柱的横向生长速率在临界Q（N2）值1.5 sccm以上迅速增加，并且在Q（N2）为3.5 sccm时变为45 nm/h。对于小于1.5sccm的低Q（N2）值，横向生长速率变得足够低，约8 nm/h;这有助于GaN的良好控制的SAG，其中底层纳米掩模图案被良好地追踪。(C)2008 Elsevier B. V.保留所有权利。
The Ti-mask selective-area growth (SAG) of GaN nanocolumns was performed at the growth temperature of 900 degrees C, while decreasing the supplied nitrogen flow rate (Q(N2)) from 3.5 to 0.5 sccm. Highly uniform arrays of GaN nanocolumns were demonstrated. At low Q(N2), both the desorption and diffusion of Ga from/on the nitrided Ti mask were accelerated, which sufficiently suppressed the crystal nucleation on the Ti-mask surface, and hence the SAG of the GaN nanocolumns was achieved even when the spacing between the nanocolumns was several hundred nm. The enhancement of Ga desorption with decreasing Q(N2) brought about a reduction in the growth rate of GaN nanocolumns from 1.05 to 0.15 mu m/h. The lateral growth rate of the GaN nanocolumns rapidly increased above the critical Q(N2) value of 1.5 sccm and became 45 nm/h at Q(N2) of 3.5 sccm. For low Q(N2) values less than 1.5 sccm, the lateral growth rate became sufficiently low, approximately 8 nm/h; this contributes to well-controlled SAG of GaN, where the underlying nanomask patterns are well traced. (C) 2008 Elsevier B.V. All rights reserved.