Research on Reliability Optimization Mechanism of 28Hkmg Technology

With the aggressive scaling down of the gate dielectric, reliability issues especially NBTI (Negative Bias Temperature Instability) and HCI (Hot Carrier Injection) become serious challenges. In this study, the critical roles of both gate dielectric thickness and DPN process are investigated in 28 nm HKMG technology. It's found that under a commercial DPN process, a certain thickness of gate dielectric is required. When this requirement is fulfilled, qualitative changes of NBTI performance could be made through DPN power optimization. And thus, a nitrogen profile modulation model is proposed to explain this significant improvement of NBTI performance after choosing a proper gate dielectric thickness and DPN process power.