Tunable bandgap and Si-doping in N-polar AlGaN on C-face 4H-SiC via molecular beam epitaxy
Tunable bandgap and Si-doping in N-polar AlGaN on C-face 4H-SiC via molecular beam epitaxy
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DOI：
10.1063/5.0173637
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发表时间：
2023-10
影响因子：
4
通讯作者：
Shubham Mondal;Ding Wang;A. F. M. Anhar Uddin Bhuiyan;Mingtao Hu;M. Reddeppa;Ping Wang;Hongping Zhao;Zetian Mi
中科院分区：
文献类型：
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作者：
Shubham Mondal;Ding Wang;A. F. M. Anhar Uddin Bhuiyan;Mingtao Hu;M. Reddeppa;Ping Wang;Hongping Zhao;Zetian Mi
n -极性AlGaN是一种新兴的宽带隙半导体，用于下一代高电子迁移率晶体管和紫外发光二极管和激光器。在这里，我们通过分子束外延在c面4h碳化硅（SiC）衬底上生长和表征了高质量的n极性AlGaN薄膜。在优化生长条件下，n -极性AlGaN薄膜具有无裂纹、原子表面光滑（均方根粗糙度~ 0.9 nm）、高晶体质量和低缺陷和位错密度。外延生长的AlGaN薄膜的n极性晶体取向通过湿化学蚀刻得到了明确的证实。我们证明了n极性AlGaN膜在广泛的Al含量范围内的精确组成可调性，以及室温下65% Al含量的AlGaN膜的高内部量子效率（74%）。此外，可控硅（Si）掺杂在高Al含量（65%）n极性AlGaN薄膜中，在电子浓度为1.1 × 1017 cm−3时，其迁移率值最高为65 cm2/V-s，而在电子浓度为3.2 × 1019 cm−3时，其迁移率值相对较高，为18 cm2/V-s，其电阻率值异常低，为0.009 Ω·cm。AlGaN在SiC上的极性控制外延为实现高质量的n -极性iii -氮化物半导体提供了一种可行的方法，可用于广泛的新兴电子和光电子器件应用。
N-polar AlGaN is an emerging wide-bandgap semiconductor for next-generation high electron mobility transistors and ultraviolet light emitting diodes and lasers. Here, we demonstrate the growth and characterization of high-quality N-polar AlGaN films on C-face 4H-silicon carbide (SiC) substrates by molecular beam epitaxy. On optimization of the growth conditions, N-polar AlGaN films exhibit a crack free, atomically smooth surface (rms roughness ∼ 0.9 nm), and high crystal quality with low density of defects and dislocations. The N-polar crystallographic orientation of the epitaxially grown AlGaN film is unambiguously confirmed by wet chemical etching. We demonstrate precise compositional tunability of the N-polar AlGaN films over a wide range of Al content and a high internal quantum efficiency ∼74% for the 65% Al content AlGaN film at room temperature. Furthermore, controllable silicon (Si) doping in high Al content (65%) N-polar AlGaN films has been demonstrated with the highest mobility value ∼65 cm2/V-s observed corresponding to an electron concentration of 1.1 × 1017 cm−3, whereas a relatively high mobility value of 18 cm2/V-s is sustained for an electron concentration of 3.2 × 1019 cm−3, with an exceptionally low resistivity value of 0.009 Ω·cm. The polarity-controlled epitaxy of AlGaN on SiC presents a viable approach for achieving high-quality N-polar III-nitride semiconductors that can be harnessed for a wide range of emerging electronic and optoelectronic device applications.