Dielectric Reliability of Stacked Al_2O_3-HfO_2 MIS Capacitors with Cylinder type for improving DRAM Data Retention characteristics

摘要

Dielectric reliability in Al_2O_3(2～3.1nm)-HfO_2(3nm) stack capacitor with Metal-Insu]ator-Si(MIS) structure is investigated in this paper, we propose an optimized capacitor process through the Time-Dependent Dielectric Breakdown (TDDB) data under various process conditions. Furthermore, due to asymmetric current at both negative and positive voltage stress polarities, we show different lifetime extrapolation by a fluence-driven model. As a result, The maximum allowed operating voltage is projected to be 1.7V (failure rate 10ppm during 10year @ 85℃) for Data"0" retention lifetime