GaN的声表面波特性研究

Study of the Surface Acoustic Wave Properties of GaN

采用金属有机物化学气相外延方法在(0001)面蓝宝石上生长了高质量、高阻的未掺杂(0001)面GaN薄膜。为精确测量GaN薄膜材料的声表面波特性,在GaN薄膜表面上沉积了金属叉指换能器,叉指换能器采用等叉指结构,叉指的数目为40对,叉指间距为15μm。采用脉冲法测量了声表面波在自由表面和金属表面上的速度,并通过计算得到了机电耦合系数(κ2)。所测量的声表面波速度(v)为5667m/s,机电耦合系数(κ2)为1 9%。

High quality and high resistivity (0001) GaN film was grown on (0001) plane sapp hire by metalorganic vapor phase epitaxy (MOVPE). To measure the surface a coustic wave (SAW) properties accurately, metallized interdigital transducers (IDT) we re deposited on the GaN surface. The pitch of the IDT was 15μm (=λ/4,λ:S AW w avelength), and the number of IDT finger pairs was 40. The surface acoustic wave velocity on free surface and that on metal surface were measured by pulse metho d respectively, and then the electromechanical coupling coefficient was calculat ed. The surface acoustic wave velocity (v) and electromechanical coupling co efficient (κ2) were measured as 5 667m/s and 19% respectively.