Semiconductor Substrate Doping Profile for Carrier Lifetime Control

The patent uses a two-step ion implantation process where first helium ions are implanted to create nucleation sites for crystalline defects, then hydrogen ions are implanted to fill these defects. The helium ions act as an intermediary that enables controlled defect formation which is subsequently healed by hydrogen, resolving the contradiction between achieving carrier lifetime control and avoiding harmful crystalline defects

The patent performs preliminary helium ion implantation before hydrogen ion implantation to pre-position defect nucleation sites. This preliminary action allows the subsequent hydrogen implantation to be more effective at controlling carrier lifetime while minimizing the formation of harmful crystalline defects, as the hydrogen fills the pre-created defect sites rather than creating new ones

The patent segments the doping process into two distinct stages: first implanting helium ions to create a specific depth profile, then implanting hydrogen ions to modify the carrier lifetime characteristics. This segmentation allows independent optimization of each implantation step, achieving complex doping concentration distributions without proportionally increasing overall process complexity

The patent changes the type of ion used for implantation (from single-element to two-element process) and adjusts implantation parameters such as energy, dose, and depth to achieve the desired doping concentration distribution. By varying these parameters systematically, the patent achieves precise carrier lifetime control while managing process complexity through standardized implantation techniques