An Extensive Study on the Boron Junctions Formed byOptimized Pre-Spike / Multiple-Pulse Flash LampAnnealing Schemes: Junction Formation, Stability andLeakage

摘要

In this work, the electrical activation of Boron in Germanium pre-amorphized silicon substrate upon flashlamp annealing (FLA) is investigated. We demonstrate that FLA helps in the reduction of the EOR defects, resulting inminimal transient enhanced diffusion and dopant deactivation effect. It has also been observed that the junction stabilityimproves with the increasing number of flash pulses, which is clearly reflected by the dopant deactivation level uponpost-thermal treatment. In another FLA scheme, the spike rapid thermal annealing (RTA) performed prior to the flashfurther enhances the junction stability. However, this pre-spike RTA step induces extensive dopant diffusion and anoverall degradation in sheet resistance. The above observations are concluded to be due to the different extent of siliconinterstitial supersaturation that can be explained by the interactions between the extended defects and dopants. Lastly,leakage current for the junctions formed under different FLA schemes are compared. Typical single pulse FLA junctionshows high leakage current and it can be reduced through the additional pulses of FLA or effectively suppressed by thepre-spike RTA flash scheme. In addition, it is also found that the junction leakage can be correlated to the FLA residualdefects