摘要
提出了一种考虑 Schottky结势垒不均匀性和界面层作用的 Si C Schottky二极管 ( SBD)正向特性模型 ,势垒的不均匀性来自于 Si C外延层上的各种缺陷 ,而界面层上的压降会使正向 Schottky结的有效势垒增高 .该模型能够对不同温度下 Si C Schottky结正向特性很好地进行模拟 ,模拟结果和测量数据相符 .它更适用于考虑器件温度变化的场合 ,从机理上说明了理想因子、有效势垒和温度的关系 .
An analytical model for forward characteristics of SiC Schottky contacts is developed taking into account the barrier inhomogeneities and interfacial layer theory.It is suggested that electrons trapped in epitaxial layer defects at the SiC/metal interface can give rise to fluctuations in the surface potential and result in lowering of the barrier height in the localized region,and thus affect the electrical I-V characteristics of the Schottky contacts.The voltage drop across the interfacial layer will raise the effective barrier height in the forward bias.The proposed model can explain the forward characteristics observed in 6H-SiC/Ti Schottky contacts from 297K to 473K.The results of experiments show good agreement with the model.The model is more suitable for SiC Schottky diode working in a wide temperature range.The increase in barrier height and decrease of ideality factor with increase of temperature are interpreted theoretically assuming a Gaussian distribution of the barrier heights.
