Abstract
Emergent alternative Si processes and devices have promoted applications outside the usual processing temperature window and the failure of traditional defect kinetics models. These models are based on Ostwald ripening mechanisms, assume pre-established defect configurations and neglect entropic contributions. We performed molecular dynamics simulations of self-interstitial clustering in Si with no assumptions on preferential defect configurations. Relevant identified defects were characterized by their formation enthalpy and vibrational entropy calculated from their local vibrational modes. Our calculations show that entropic terms are key to understand defect kinetics at high temperature. We also show that for each cluster size, defect configurations may appear in different crystallographic orientations and transformations among these configurations are often hampered by energy barriers. This induces the presence of non-expected small-size defect cluster configurations that could be associated to optical signals in low temperature processes. At high temperatures, defect dynamics entails mobility and ripening through a coalescence mechanism.
Highlights
Ion implantation is a widely used technology to introduce dopants in semiconductor devices
We show that for each cluster size, defect configurations may appear in different crystallographic orientations and transformations among these configurations are often hampered by energy barriers
As active dopants occupy lattice positions, a Si self-interstitial excess is generated [1]. These particles diffuse and interact during annealing treatments, resulting in the formation of more complex selfinterstitial clusters. Their evolution is conventionally modeled through an Ostwald Ripening mechanism, in which big and more stable defects grow by the capture of Si self-interstitials emitted by smaller and less stable defects
Summary
Ion implantation is a widely used technology to introduce dopants in semiconductor devices. As active dopants occupy lattice positions, a Si self-interstitial excess is generated [1] These particles diffuse and interact during annealing treatments, resulting in the formation of more complex selfinterstitial clusters. On the one hand, extended {001} loops have been obtained after few nanoseconds in sub-melting laser annealed ion-implanted Si [7] The formation of these extended defects is incompatible with an Ostwald Ripening growth process as it would require more than a few nanoseconds for these extended defects to form through the dissolution of small clusters and the growth of the larger and more stable clusters. In this work we discuss how the variability of defect configurations affects in low temperature processes, and how alternative defect growth mechanisms have to be considered in the high temperature regime For this purpose, we have combined our previous findings on atomistic modeling of Si selfinterstitial clusters with new results that help to extend traditional models of defect kinetics
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
