H+ implantation profile formation in m:Cz and Fz silicon

摘要

Implanting hydrogen ions (H) into silicon creates defects that can act as donors. The microscopic structure of these defects is not entirely clear. There is a difference in the resulting doping profiles if the silicon is produced by the float zone (Fz) process or the magnetic Czochralski (m:Cz) process. Silicon produced by the m:Cz process has higher concentrations of oxygen and carbon than silicon produced by the Fz process. The presence of the oxygen and carbon affects the formation of defects and thereby the doping profile. We implanted high resistivity p-type m:Cz and Fz wafers with protons. Due to the n-type doping from the H implantation, a pn-junction was generated in the sample. Simulations indicate that the H implantation depth is 148 µm. Spreading Resistance Profiling (SRP) measurements of as-implanted and not annealed samples show a donor peak at 148 µm in the Fz samples but the peak is at about 160 µm depth in m:Cz samples. After a low temperature anneal of the m:Cz samples at temperatures between 150 and 250 °C for at least 30 minutes, the expected end of range (EOR) donor peak (at about 148 µm) appears. For higher annealing temperatures, the hydrogen related donor complexes (HTD's) become activated and the EOR peak becomes dominant in the implantation profile. In an SRP study we show the evolution of the doping profile of hydrogen implanted m:Cz and Fz wafers as a function of the annealing temperature. To monitor the depth of the formed pn-junction and the effective local diffusion length in the proton radiation damaged region, Electron Beam Induced Current (EBIC) measurements were performed.