Metalorganic chemical vapor phase deposition of AlScN/GaN heterostructures
Metalorganic chemical vapor phase deposition of AlScN/GaN heterostructures
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AlScN/GaN异质结构的金属有机化学气相沉积
DOI：
10.1063/5.0003095
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发表时间：
2020-05
影响因子：
3.2
通讯作者：
Jana Ligl;S. Leone;C. Manz;L. Kirste;Philipp Doering;Theodor Fuchs;M. Prescher;O. Ambacher
中科院分区：
文献类型：
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作者：
Jana Ligl;S. Leone;C. Manz;L. Kirste;Philipp Doering;Theodor Fuchs;M. Prescher;O. Ambacher
由于AlScN/GaN异质结界面具有显著的高自发极化梯度，使其在高功率、高频电子领域具有广阔的应用前景，因此具有重要的研究价值。本工作采用金属有机化学气相沉积方法生长了用于高电子迁移率晶体管(HEMT)结构的AlScN/GaN异质结。我们研究了生长参数对厚层AlScN和薄AlScN/GaN异质结的影响。温度、V/III比、压力和生长模式等生长参数随着表面形貌、晶体质量和杂质掺杂的不同而变化。较高的生长温度改善了表面质量，并显著减少了杂质的掺入。此外，通过采用脉冲供应金属有机前驱体，碳浓度也略有下降。V/III比和压力对膜层质量没有显著影响。获得了均方根表面粗糙度低至0.38 nm的异质结，显示出平滑的生长步骤。片载流子密度和迁移率分别高达2×1013 cm−2和接近900cm2/(V S)的二维电子气的存在使沟道方阻低至337cm2/sq，非常适合于AlScN/GaN HEMT。异质结的方阻小于2 0 0Ω/sq，方块载流子密度为5×10 13 cm−2，但迁移率明显降低。
AlScN/GaN heterostructures are worth investigating due to the remarkable high gradients in spontaneous polarization at their interfaces, which brings them into play for a wide field of potential high-power and high-frequency electronic applications. In this work, AlScN/GaN heterostructures for high electron mobility transistor (HEMT) structures were grown by metalorganic chemical vapor deposition. We have investigated the impact of growth parameters on thick AlScN layers and on thin AlScN/GaN heterostructures. Growth parameters, such as temperature, V/III ratio, pressure, and growth mode, were varied with the focus on surface morphology, crystal quality, and incorporation of impurities. High growth temperatures improve the surface quality and reduce impurities incorporation notably. In addition to that, a slight decrease in carbon concentration is obtained by adopting a pulsed supply of metalorganic precursors. V/III ratio and pressure did not influence the layer quality observably. Heterostructures with root mean square surface roughness values as low as 0.38 nm, revealing smooth growth steps, were achieved. The presence of two-dimensional electron gases with sheet carrier densities and mobilities of up to 2 × 1013 cm−2 and close to 900 cm2/(V s), respectively, resulted in channel sheet resistances as low as 337 Ω/sq, very suitable for AlScN/GaN HEMTs. Heterostructures with sheet resistances below 200 Ω/sq and sheet carrier densities of 5 × 1013 cm−2 were also achieved but showed significantly lower mobility.