Time-dependent-dielectric-breakdown characteristics of Hf-doped Ta₂O₅/SiO₂ stack

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• 作者：E. Atanassova ; N. Novkovski ; D. Spassov ; A. Paskaleva ; A. Skeparovski
• 刊名：Microelectronics Reliability
• 出版年：February, 2014
• 年：2014
• 卷：54
• 期：2
• 页码：381-387
• 全文大小：840 K

文摘

The Time-Dependent-Dielectric Breakdown (TDDB) characteristics of MOS capacitors with Hf-doped Ta₂O₅ films (8 nm) have been analyzed. The devices were investigated by applying a constant voltage stress at gate injection, at room and elevated temperatures. Stress voltage and temperature dependences of hard breakdown of undoped and Hf-doped Ta₂O₅ were compared. The doped Ta₂O₅ exhibits improved TDDB characteristics in regard to the pure one. The maximum voltage projected for a 10 years lifetime at room temperature is 鈭?.4 V. The presence of Hf into the matrix of Ta₂O₅ modifies the dielectric breakdown mechanism making it more adequate to the percolation model. The peculiarities of Weibull distribution of dielectric breakdown are discussed in terms of effect of three factors: nature of pre-existing traps and trapping phenomena; stress-induced new traps generation; interface layer degradation.