【摘要】 提出一种新的钝化技术——采用盐酸和氢氟酸混合预处理溶液(HF:HCl:H2O=1:4:20)对AlGaN/GaNHEMTs进行表面预处理后再淀积Si3N4钝化,研究了新型钝化技术对AlGaN/GaNHEMTs性能的影响并分析其机理.与用常规方法钝化的器件相比,经过表面预处理再钝化,成功地抑制了AlGaN/GaNHEMTs肖特基特性的恶化,有效地增强抑制电流崩塌效应的能力,将GaN基HEMTs的输出功率密度提高到5.2W/mm,并展现良好的电学可靠性.通过X射线光电子谱(XPS)检测预处理前后的AlGaN表面,观察到经过预处理后的AlGaN表面氧元素的含量大幅度下降.表面氧元素的含量下降,能有效地降低表面态密度和表面电荷陷阱密度,被认为是提高AlGaN/GaNHEMTs性能的主要原因.更多还原

【Abstract】 A passivation method is developed,and the effects and mechanism of this passivation method on the performance of AlGaN/GaN HEMTs and are investigated.The key aspect of this passivation technique is that AlGaN/GaN HEMTs are pretreated with a mix of hydrochloric acid and hydrofluoric acid(HF:HCl:H2O=1:4:20) prior to Si3N4 deposition.Compared with devices passivated only with Si3N4 deposition,the devices fabricated with the mixing solution treatment prior to Si3N4 passivation show minimal gate reverse leakage and little current collapse effect induced by DC bias stress.The density of the output power increases to 5.2W/mm,exhibiting good electrical reliability.X-ray photoelectron spectroscopy is employed to measure the AlGaN surface before and after pretreatment.The decrease of the oxygen ratio in the AlGaN surface after surface treatment reduces the concentration of surface states and surface charge traps,which is regarded as the major reason for the performance improvement of AlGaN/GaN HEMTs.更多还原