EXPERIMENTAL ANALYSIS OF CONCENTRATION PROFILES OF BORON IMPLANTED

The concentration profiles of boron implantations in silicon are measured using secondary ion mass spectrometry. In this method the implanted silicon is sputtered by b~mbardment with 5.5 keV oxygen ions. The resulting secondary B -current is measured continuously as a function of time. The time scale is transformed into a depth scale by measuring the erosion rate. The reliability of this method is checked and discussed. This method is used in the study of the specific shape of the profiles of boron implanted in a dense crystal direction. This was done by varying the implantation conditions such as temperature, crystal direction, crystal perfection. The boron profiles in amorphous silicon were compared with theory. Another aspect studied is the profile distortion due to heat treatments. By comparison of the boron profiles with corresponding electrical profiles valuable addi­ tional information was obtained.