AI 中文总结
研究针对低对称性β-Ga2O3，利用有大生长内斜切角的(100)Ga2O3晶圆，通过分子束外延生长，经化学机械抛光等处理，实现快速同质外延，制备出性能良好的肖特基势垒二极管，验证了该取向晶圆及晶面和斜切角的重要性。
AI 中文摘要
对于低对称性的β-Ga2O3，晶体取向和斜切角的选择并非易事，各向异性会影响体材料和薄膜合成、材料性能以及功率器件制造与性能。可扩展的(100)取向β-Ga2O3晶圆对电子器件很理想，但因其生长速率比其他取向慢10至30倍而不常使用。本文报告通过使用具有大生长内斜切角的(100)Ga2O3晶圆，分子束外延（MBE）生长速率等同于快速生长方向。通过二维带状物的边缘限定膜馈生长（EFG）和旋转籽晶直接生长斜切角（高达13.4°），避免了晶体块斜切方法造成的材料损失，同时保持高晶体质量。化学机械抛光制备出适于外延的衬底，在所有斜切角都观察到台阶流生长。测量到无意n型掺杂密度为2×10^15 cm^-3，是MBE生长薄膜报告的最低值之一。这些外延层上无边缘终止的平面肖特基势垒二极管的开/关比约为10^5，平均击穿场为1.56 MV/cm，与其他取向制造的类似器件相当或更高。总体而言，这些结果说明了晶面和斜切角的重要性，并验证了可扩展的(100)取向β-Ga2O3晶圆的使用。
英文摘要
The choice of crystalline orientation and offcut angle is non-trivial for low-symmetry $β\text{-Ga}_2\text{O}_3$, where anisotropy impacts bulk and thin film synthesis, material properties, and power device fabrication and performance. Scalable (100)-oriented $β\text{-Ga}_2\text{O}_3$ wafers are desirable for electronic devices but are not typically used due to 10-30x slower growth rates compared to other orientations. Here we report molecular beam epitaxy (MBE) growth rates equal to the fast growth direction by using (100) $Ga_2O_3$ wafers with large grown-in offcuts. The offcuts (up to 13.4°) are directly grown by Edge-defined Film-fed Growth (EFG) of 2D ribbons with rotated seed crystals, avoiding material loss from crystal boule offcut methods while maintaining high crystalline quality. Chemical-mechanical polishing produces epitaxy-ready substrates, and step flow growth is observed across all offcut angles. We measure an unintentional n-type doping density of $2{\times}10^{15} cm^{-3}$, one of the lowest values reported for MBE-grown films. Planar Schottky barrier diodes on these epilayers without edge termination have an on/off ratio ~10$^5$ and an average breakdown field of 1.56 MV/cm, comparable to or exceeding similar devices fabricated on other orientations. Overall, these results illustrate the importance of both crystal face and offcut angle and validate the use of the scalable (100)-oriented $β\text{-Ga}_2\text{O}_3$ wafers.
