无凹槽AlGaN/GaN肖特基势垒二极管正向电流输运机制

研究了无凹槽AlGaN/GaN肖特基势垒二极管(SBD)的正向电流输运机制。分别采用Ni/Au和TiN作为阳极金属材料制备了无凹槽AlGaN/GaN SBD,对比了两种SBD的直流特性。并通过测量器件的变温I-V特性,研究了器件的正向电流输运机制。结果表明,TiN-SBD(0.95 V@1 mA·mm^-1)与Ni/Au-SBD(1.15 V@1 mA·mm^-1)相比实现了更低的开启电压,从而改善了正向导通特性。研究发现两种SBD的势垒高度和理想因子都强烈依赖于环境温度,通过引入势垒高度的高斯分布模型解释了这种温度依赖性,验证了正向电流输运机制为与势垒高度不均匀分布相关的热电子发射机制。

Forward Current Transport Mechanism of Recess-Free AlGaN/GaN Schottky Barrier Diodes

The forward current transport mechanism of the recess-free AlGaN/GaN Schottky barrier diodes ( SBDs) were studied. Recess-free AlGaN/GaN SBDs were fabricated by using Ni/Au and TiN as anode metal materials respectively, and the DC characteristics of two kinds of SBDs were compared. The forward current transport mechanism of the devices were studied by measuring the voltage-current characteristics at different temperatures. The results show that compared with the Ni/Au-SBD (1.15 V @1 mA·mm^-1), a lower turn-on voltage of the TiN-SBD ( 0. 95 V@ 1 mA·mm^-1 ) is achieved and the forward conduction characteristic is improved. It is found that the potential barrier height and ideality factor of both SBDs are strongly depend on the ambient temperature. The temperature dependence is explained by introducing the Gaussian distribution model of the potential barrier height, and the forward current transport mechanism is verified as the thermionicemission mechanism related to the inhomogeneous distribution of the potential barrier height.