The thermal behavior of crystalline silicon coimplanted with boron and hydrogen.

摘要

A method was developed to convert reflection elastic recoil detection analysis (ERDA) spectra to depth profiles: A technique referred to as the energy spread correction corrects for the broadening in the energy of the spectra, which causes depth profiling errors. A second technique, the channel-depth conversion, coverts the corrected ERDA spectra into depth profiles. Together, the two techniques comprise an accurate and convenient hydrogen depth profiling method. These techniques rely on accurate calibration of the ERDA experimental setup, therefore calibration techniques are presented also.; The hydrogen depth profiling method was developed as part of an extensive investigation into the thermal behavior of crystalline silicon coimplanted with boron and hydrogen. The results of that investigation are presented in three parts. (1) The thermal evolution of hydrogen and defects during elevated-temperature hydrogen implantation of boron-preimplanted silicon: In the low temperature regime, trapping by impurities and defects inhibits hydrogen diffusion, while the defect structure is enhanced or suppressed for activated or non-activated samples, respectively. At high temperature the lattice experiences boron-enhanced, ion beam-induced recrystallization, accompanied by damage evolution toward extended defects, in which hydrogen diffusion proceeds by the formation and dissociation of substitutional boron-hydrogen complexes. (2) The wholesale displacement of the hydrogen and defects during elevated-temperature hydrogen implantation of boron-preimplanted silicon: Shifts in the hydrogen distribution were observed for boron preimplanted shallower than hydrogen. The silicon displacement defect structure experiences a correlated shift to a location other than the initial location of the implantation damage, indicating that it is hydrogen-induced. The displacement of the distributions is attributed to substitutional boron-enhanced diffusion of hydrogen to trapping centers, which consist of boron atoms and the hydrogen-induced defect structure. (3) In situ surface blistering was observed during elevated-temperature hydrogen implantation of boron-preimplanted silicon: The observed effects are attributed to impurities, and their electrical activation by thermal annealing. Boron is found to enhance surface blistering kinetics. In some cases, craters were observed to form at shallower depths, attributed to boron-enhanced hydrogen diffusion to trapping centers, which prevent hydrogen evacuation, leaving a sufficient concentration to form craters.