Thermal evolution of surface blistering and exfoliation due to ion-implanted hydrogen monomers into Si〈1 1 1〉

Abstract

This study investigated the dependence of surface blistering and exfoliation phenomena on post-annealing time in H+-implanted Si〈111〉. Czochralski-grown n-type Si〈111〉 wafers were room-temperature ion-implanted with 40keV hydrogen monomers to a fluence of 5×1016cm−2, and followed by furnace annealing treatments at 400 and 500°C for various durations ranging from 0.25 to 3h. The corresponding analysis results for Si〈100〉 [1] (Liang et al., 2008); [2] (Bai, 2007) were adopted in order to make comparisons. The evolution of blister formation and growth for Si〈111〉 at 400°C has a shorter characteristic time compared to Si〈100〉. However, there is a longer characteristic time when annealing takes place at 500°C. In addition, no craters were observed for Si〈111〉 annealed at 400°C while the opposite is true for Si〈100〉. The evolution of crater development for Si〈111〉 annealed at 500°C has a longer characteristic time compared to Si〈100〉. These results are attributed to the fact that compared to Si〈100〉, Si〈111〉 has a smaller surface binding energy of silicon atoms and a larger areal number density of silicon atoms on the plane perpendicular to the incident-ion axis. Furthermore, Si〈111〉 has a greater areal number density, smaller diameter, and a similar covered-area fraction of optically-detectable blisters compared to Si〈100〉. However, Si〈111〉 has a lower areal number density and a smaller covered-area fraction of craters than does Si〈100〉. Increasing post-annealing temperature from low (e.g. 400°C) to high (e.g. 500°C) revealed that Si〈111〉 tends to create more blisters while Si〈100〉 tends to develop larger blisters as well as create more craters.