Study On Damage And Mechanism In Crystal Silicon Co-implanted With Boron And Light Gas Ions

’Smart-Cut’is a novel, promising production technology of silicon-on-insulator (SOI) systems. Ever since it was reported for the first time by Bruel, this technology has attracted more attentions and found practical applications in the field of SOI. The ’Smart-Cut’is mainly based on hydrogen implantation and wafer bonding. The standard’Smart-Cut’technique is confronted by either the high doses or high thermal budget for layer cleavage, which inevitably leads to high cost of production. In order to promote the commercial application of such technique, co-implantation of multiple ions have been presented to reduce the total fluence and annealing temperature for exfoliation. In the work, main results on the defect creation in silicon wafer singly and sequentially implanted with B and H ions are presented, and the underlying mechanism for the promotion effect has tentatively been proposed. In addition, the crystalline silicon wafer was also co-implanted with He, B and H ions, and its surface blistering and evolution of the vacancy-type defects have been investigated. The research contents and corresponding results are given as follows:(1) Cz n-type Si (100) wafers were singly and/or sequentially implanted at room temperature with130keV B ions at a fluence of5X1014cm-2and55keV H ions at a fluence of1X1016cm-2. The implantation-induced defects were investigated in detail by using cross-sectional transmission electron microscopy (TEM) and positron annihilation spectroscopy (PAS). TEM results clearly show that sequential implantation of B and H ions into silicon could eliminate the (111) platelets and promote the growth of (100) platelets during annealing. PAS measurements demonstrate that in the B and H ions sequentially implanted and annealed sample, more vacancy-type defects could remain in sample region around the range of B ions. These results indicate that the promotion effect should be attributed to the role of both B ions and B implantation-induced vacancy-type defects.(2) By means of optical microscopy (OM), atomic force microscopy (AFM) and positron annihilation spectroscopy (PAS), Si (100) wafers singly and/or sequentially implanted with He, B and H ions were investigated tentatively. The energies of He, B and H ions were60keV,130keV and40keV, and their fluences were of lx1016cm-2,5x1014cm-2and2x1016cm-2, respectively. OM results clearly show that the number of the surface blistering increases significantly for the He, B and H ions sequentially implanted sample after400℃annealing. AFM results indicate that the depth of the popped-off caters is same in the B and H ions sequentially implanted sample and He, B and H ions sequentially implanted sample, indicating that He ions diffuse toward the region where B and H ions are located. PAS results reveal the evolution process of vacancy-type defects in the He single implanted sample. The above results indicate that He, B and H ions sequential implantation could enhance the surface blistering and exfoliation in the crystalline silicon.