GaN基HEMT器件抗逆压电性能研究

可靠性问题是GaN基HEMT器件走向实用化的关键,逆压电效应导致器件退化是近年来比较引人瞩目的理论之一。对于GaN基HEMT器件,当其承受外加电场时,由于逆压电效应,电场最终转化成弹性势能。当电场足够大,突破势垒层材料所能承受的临界弹性势能,势垒层材料就会发生松弛。根据逆压电效应导致器件退化机理,从弹性势能的角度出发,对低Al组分AlGaN势垒层、InAlN势垒层和AlGaN背势垒等三种结构进行理论分析。分析表明,三种结构均能较大程度地改善GaN基HEMT器件的抗逆压电能力,从而提高器件可靠性。

Anti-Inverse Piezoelectric Effect Performance for the GaN-Based High Electron Mobility Transistors

The reliability issue is the key concern for the massive practical application of the GaN-based high electron mobility transistors(HEMTs),and the devices degradation caused by inverse piezoelectric effect(IPE)has attracted most attention in recent years.For the GaN-based HEMTs,the external electric field applied would transform to the elastic energy due to the IPE.When the electric field applied is high enough,the elastic energy in barrier layer is large enough to exceed a critical value,leading to the relaxation of the barrier layer.According to the degradation mechanisms of IPE,the theoretical analysis on the AlGaN barrier layer of low Al mole fraction,the InAlN barrier layer and the AlGaN barrier layer,from the aspect of elastic energy were performed.The results show that,these three structures proposed would improve the anti-IPE performance of the GaN-based HEMTs much,leading to the better reliability consequently.