面对面退火温度控制用于AlGaN电力电子器件的Ta(C,N)虚拟衬底中的晶格参数

中文摘要 AI 辅助

碳化钽（TaC）薄膜“虚拟”衬底是Al0.5Ga0.5N垂直电力电子器件非常理想的材料，因为它具有晶格匹配、热膨胀匹配和金属导电性。然而，该材料尚未被证明能够支持可变组分x的AlxGa1-xN层，限制了器件应用的范围。我们提出了一种通过在N2气氛中对TaC薄膜进行面对面退火来实现可调谐岩盐TaCxN1-x虚拟衬底的方法。结果表明，低于1600°C的退火温度促进氮部分占据碳和阴离子空位位点，形成具有中间阴离子组分的岩盐Ta(C,N)。在≥1600°C的温度下，氮主要占据阴离子亚晶格，晶体质量和表面形貌同时恶化，并伴随第二相的形成。本研究展示了从x=0.5-1制备用于AlxGa1-xN的可调晶格常数虚拟衬底所需的生长和加工参数，使得在高Al含量下具有降低缺陷密度的垂直导电电力电子器件成为可能。

英文摘要

Tantalum carbide (TaC) thin film ''virtual'' substrates are a highly desirable material for $\text{Al}_{0.5}\text{Ga}_{0.5}\text{N}$ vertical power electronics devices due to lattice matching, thermal expansion matching, and metallic conductivity. However, the material has not been demonstrated to support $\text{Al}_{x}\text{Ga}_{1-x}\text{N}$ layers of variable composition $x$, limiting the range of device applications. We present a method to achieve tunable rock salt $\text{Ta}\text{C}_{x}\text{N}_{1-x}$ virtual substrates via a face-to-face annealing of TaC thin films in an $\text{N}_2$ atmosphere. The results suggest that annealing temperatures below $1600\,^{\circ}\text{C}$ promote partial uptake of nitrogen onto carbon and anion vacancy sites to form rock salt $\text{Ta(C,N)}$ with intermediate anion compositions. At temperatures $\ge 1600\,^{\circ}\text{C}$, nitrogen primarily occupies the anion sublattice and the crystalline quality and surface morphology simultaneously degrade coincident with the formation of secondary phases. This study demonstrates the growth and processing parameters necessary to make tunable lattice constant virtual substrates for $\text{Al}_{x}\text{Ga}_{1-x}\text{N}$ from $x = 0.5\text{-}1$, enabling vertically conducting power electronic devices with reduced defect density at high Al-content.

发表机构

• Rossin College of Engineering, Lehigh University（利哈伊大学罗辛工程学院）
• National Laboratory of the Rockies（落基山国家实验室）

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