n-GaAs Ti/Mo/Ti/Au中肖特基势垒接触稳定性的研究

Stability of Schottky Contact in n-GaAs Ti/Mo/Ti/Au

摘要: 对Ti/Mo/Ti/Au作为栅金属的GaAsMESFET进行了高温反偏(HTRB)、高压反偏(HRB)、高温正向大电流(HFGC)、高温存贮(HTS)4种不同的应力试验.通过HRB,φb从0.64eV减少到0.62eV,理想因子n略有增大,HTS试验中φb从0.67eV增加到0.69eV.分析表明,这归因于界面氧化层的消失,以及Ti与GaAs的反应;HFGC试验结果表明,其主要的失效模式为烧毁,同时,SEM观察中也有电徙动及断栅现象发生.AES分析表明,应力试验后的样品,其肖特基势垒接触界面出现模糊,有明显的互扩散和反应发生.

Abstract: In this paper,the Ti/Mo/Ti/Au Schottky barrier contact in GaAs MESFETs were investigated by means of:(1) high reverse biased test (HRB). (2) high temperature reverse biased (HTRB).(3) high temperature forword gate current (HFGC).(4) high temperature storage (HTS).The tests show that the barrier height φ_b decrease from 0.64ev to 0.62eV in HRB test,while in HTS, the φ_b increase from 0.67eV to 0.69eV, due to the disappearance of interface oxide layer and the interaction of Ti to GaAs.During HFGC test,the main failure mode is burnout,SEM analysis finds electromigration and ungate phenomena appearing simultaniously.AES indicates that interaction, between gate metallization and GaAs active layer, happens and the Schottky contact interface becomes ambiguous after stressing.