Fabrication of periodically poled AlN with sub-micron periods
Fabrication of periodically poled AlN with sub-micron periods
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具有亚微米周期的周期性极化 AlN 的制造
DOI：
10.1002/pssc.201001163
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
M. Wraback
中科院分区：
文献类型：
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作者：
Jonathan Wright;C. Moe;A. Sampath;G. Garrett;M. Wraback
我们报道了用感应耦合等离子体(ICP)刻蚀和等离子体辅助分子束外延(PAMBE)制备周期性极化的AlN结构。周期极化AlN结构的制备方法是先在c面蓝宝石衬底上沉积Al极性材料，然后通过镁过掺杂实现极性反转。随后，通过电子束光刻确定了周期在250-750 nm之间的光栅，并通过感应耦合等离子体刻蚀将其刻蚀到薄膜中，以曝光铝极性材料的条纹。对电感耦合等离子体刻蚀进行了优化，以产生垂直侧壁和平滑的铝极区。最后，利用PAMBE对图案化的衬底进行再生长，实现周期性极化的AlN结构。Al和N极区之间界面的锐度取决于再生长过程中的电感耦合等离子体刻蚀条件和III-V通量。在富III的条件下，光栅与晶体取向的对准对最终的表面形貌具有重要的作用。虽然较低的III-V通量比阻止了刻面，但在高宽高比的沟槽侧壁附近，铝极材料的再生长受到抑制。(2011Wiley-VCH Verlag GmbH&Co.KGaA，Weinheim)
We report on the fabrication of periodically poled AlN structures using inductive coupled plasma (ICP) etching and plasma-assisted molecular beam epitaxy (PAMBE). Periodically poled AlN structures are fabricated by first depositing Al polar material on c-plane sapphire substrates and then inverting the polarity through Mg overdoping. Subsequently, a grating with periods between 250 and 750 nm is defined by e-beam lithography and etched into the film by inductive coupled plasma etching to expose stripes of Al-polar material. ICP etching was optimized to produce vertical sidewalls and smooth Al-polar regions. Finally, the patterned substrate is regrown by PAMBE to realize a periodically poled AlN structure. The sharpness of the interface between the Al and N polar regions is found to be dependent upon ICP etch conditions and III-V flux during regrowth. Under III-rich conditions, the alignment of the grating with crystallographic orientation has an important role in the final surface morphology. While lower III-V flux ratios prevent faceting, regrowth of Al-polar material is inhibited near the sidewalls of trenches with high aspect ratios. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)