Controlling Residual Stress and Suppression of Anomalous Grains in Aluminum Scandium Nitride Films Grown Directly on Silicon
Controlling Residual Stress and Suppression of Anomalous Grains in Aluminum Scandium Nitride Films Grown Directly on Silicon
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DOI：
10.1109/jmems.2022.3167430
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发表时间：
2022-05-06
影响因子：
2.7
通讯作者：
Olsson, Roy H., III
中科院分区：
文献类型：
--
作者：
Beaucejour, Rossiny;Roebisch, Volker;Olsson, Roy H., III
采用反应共溅射法在硅衬底上直接沉积氮化铝钪（AlScN）薄膜，其沉积条件为高Sc合金化水平、可控应力、无反常晶粒（AOG）。平均应力和AOG形成考虑Sc合金化范围在20.3和36.6原子%之间，并且对于27.3%和31.7%的Sc合金化，膜厚度从400 nm到1000 nm。梯度种子层和适当的工艺气体混合物的组合被示出抑制AOG的形成在AlScN与高达36%的Sc合金化，即使当直接生长在Si上。它表明，总流量可以用来控制平均膜应力在20-36%的掺杂范围，而工艺气体混合物主要影响AOG形成的AlScN膜的密度。由直接生长在Si上的380 nm和485 nm厚的低应力和无AOG的Al 0.68 Sc 0.32 N膜制造的体声波谐振器展示了3.6和4.8 GHz的高频操作、> 20%的高机电耦合和超过500的品质因数。
Deposition of Aluminum Scandium Nitride (AlScN) films directly on Silicon at high Sc alloying levels, with controlled stress, and free of anomalous grains (AOGs) is demonstrated using reactive co-sputtering. The average stress and AOG formation consider the Sc alloying range between 20.3 and 36.6 atomic % and for film thicknesses from 400 nm to 1000 nm for 27.3% and 31.7% Sc alloying. The combination of a gradient seed layer and proper process gas mixture is shown to inhibit formation of AOGs in AlScN with up to 36% Sc alloying even when grown directly on Si. It is demonstrated that the total flow can be utilized to control the average film stress across the 20-36% doping range while the process gas mixture primarily impacts the density of AOG formation in the AlScN films. Bulk acoustic wave resonators fabricated from 380 nm and 485 nm thick low stress and AOG free Al0.68Sc0.32N films grown directly on Si demonstrate high frequency operation of 3.6 and 4.8 GHz, high electromechanical coupling >20%, and quality factors in excess of 500.