Ma Yulin, Wang Xu, Ma Kui
Department of Electronic Science, Guizhou University, Guiyang 550025, China.
Key Laboratory of Micro-Nano-Electronics and Software Technology of Guizhou Province, Guiyang 550025, China.
Micromachines (Basel). 2025 Sep 10;16(9):1035. doi: 10.3390/mi16091035.
Aluminum nitride (AlN), a III-V wide-bandgap semiconductor, has attracted significant attention for high-temperature and high-power applications. However, achieving p-type doping in AlN remains challenging. In this study, p-type AlN thin films were fabricated via magnetron sputtering using Mg-Al alloy targets with varying Mg concentrations (0.01 at.%, 0.02 at.%, and 0.5 at.%), followed by ex situ high-temperature annealing to facilitate Mg diffusion and electrical activation. The structural, morphological, and electrical properties of the films were systematically characterized using X-ray diffraction (XRD), white light interferometry (WLI), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and Hall effect measurements. The results demonstrate that at a Mg doping concentration of 0.02 at.%, the films exhibit optimal crystallinity, uniform Mg distribution, and a favorable balance between carrier concentration and mobility, resulting in effective p-type conductivity. Increasing Mg doping leads to higher surface roughness and the formation of columnar and conical grain structures. While high Mg doping (0.5 at.%) significantly increases carrier concentration and decreases resistivity, it also reduces mobility due to enhanced impurity and carrier-carrier scattering, negatively impacting hole transport. XPS and EDS analyses confirm Mg incorporation and the formation of Mg-N and Al-Mg bonds. Overall, this study indicates that controlled Mg doping combined with high-temperature annealing can achieve p-type AlN films to a certain extent, though mobility and carrier activation remain limited, providing guidance for the development of high-performance AlN-based bipolar devices.
氮化铝（AlN）是一种III-V族宽带隙半导体，因其在高温和高功率应用方面的潜力而备受关注。然而，实现AlN的p型掺杂仍然具有挑战性。在本研究中，通过磁控溅射使用不同Mg浓度（0.01 at.%、0.02 at.%和0.5 at.%）的Mg-Al合金靶制备p型AlN薄膜，随后进行非原位高温退火以促进Mg扩散和电激活。使用X射线衍射（XRD）、白光干涉测量法（WLI）、扫描电子显微镜（SEM）、能量色散X射线光谱（EDS）、X射线光电子能谱（XPS）和霍尔效应测量对薄膜的结构、形貌和电学性质进行了系统表征。结果表明，当Mg掺杂浓度为0.02 at.%时，薄膜表现出最佳的结晶度、均匀的Mg分布以及载流子浓度和迁移率之间的良好平衡，从而实现了有效的p型导电性。增加Mg掺杂会导致更高的表面粗糙度以及柱状和锥形晶粒结构的形成。虽然高Mg掺杂（0.5 at.%）显著增加了载流子浓度并降低了电阻率，但由于杂质和载流子-载流子散射增强，迁移率也会降低，对空穴传输产生负面影响。XPS和EDS分析证实了Mg的掺入以及Mg-N和Al-Mg键的形成。总体而言，本研究表明，尽管迁移率和载流子激活仍然有限，但可控的Mg掺杂与高温退火相结合可以在一定程度上实现p型AlN薄膜，为高性能AlN基双极器件的开发提供了指导。
