表面化学处理和退火对p-GaN/ZnO:Ga接触特性的影响

Effects of Surface Chemical Treatment and Annealing on p-GaN/ZnO:Ga Contact

ZnO∶Ga(GZO)透明电极沉积在p-GaN表面,用作透明电流扩展层。直接沉积在p-GaN上的p-GaN/GZO存在较大的势垒,容易形成肖特基接触,而良好的欧姆接触对功率LED器件至关重要。为了降低接触势垒,采用盐酸和氢氧化钠溶液对GaN表面进行去氧化层处理,并对p-GaN/GZO进行退火处理,研究表面处理和退火对p-GaN/GZO接触特性的影响。研究表明:碱性溶液处理有利于降低接触势垒;退火处理后,接触势垒略有增加。

ZnO∶Ga（GZO） transparent conductive thin film was deposited on p-GaN acting as the current spreading layer,but it leads to a large contact barrier because of the formation of Schottky contact.However,ohmic contact is of great importance to powered LED.In order to decrease the contact barrier,HCl and NaOH treatment of the p-GaN surface and annealing were employed in this work.The effects of different chemical treatment and annealing on p-GaN/GZO contact property were studied.It is obvious that solutions of alkaline treatment of p-GaN surface can decrease the interfacial barrier,which led to ohmic contact,and the barrier can be lightly increased by annealing.