Hg_(1-x)Cd_xTe N^+-P栅控二极管表面沟道漏电的理论和实验研究

EXPERIMENTAL AND THEORETICAL INVESTIGATIONS OF SURFACE CHANNEL LEAKAGE CURRENT IN Hg_(1-x)Cd_xTe N^+-P GATE-CONTROLLED PHOTODIODES

制备了HgCdTe离子注入N^+-P栅控二极管.测量结果表明,由P区一侧表面强反型引起的表面沟道漏电严重限制着器件性能,对这种漏电机制进行了详细的理论分析.在考虑了窄禁带HgCdTe的特殊性质后,计算了表面沟道电流决定的P-N结正、反向I-V特性和R_0A的温度特性,以及它们与表面状态的关系.理论与实验定性相符.

Hg_(1-x)Cd_xTe ion-implanted N^+-P gate-controlled photodiodes are fabricated.Measurements show that the P-N junction characteristics are limited seriously by surface channel leakage current due to strong inversion of P-side surface. A theoretical analysis about this leakage mechanism is carried out in detail. By taking into account the unique features of narrow band-gap Hg_(1-x)Cd_xTe, forward and reverse I-V characteristics and the temperature dependence of R_0A product determined by surface channel current are calculated as a function of the gate bias. A qualitative agreement between experimental and the-oretical results is obtained.