Detection of Vacancy Distributions by Decoration with Hydrogen

Abstract

A well-known method for the determination of vacancy distributions in silicon is based on the decoration of vacancies with in-diffused platinum (Pt) and subsequent profiling of the Ptdistribution with DLTS (Deep Level Transient Spectroscopy) analysis. The vacancy profile can then be correlated with the substitutional Pt profile. However, there are significant drawbacks of this method: The in-diffusion of platinum is a high-temperature step, which already can alter the vacancy profile; moreover, DLTS measurements with a suitable depth resolution are time-consuming and difficult. Therefore, it is proposed in this paper to decorate the vacancies with hydrogen by processes finally resulting in the formation of vacancy-and hydrogen-related donor and acceptor states. The determination of such doping profiles and by this the detection of vacancy distributions can be easily enabled by depthresolved spreading resistance measurements with a very good spatial resolution. Hydrogen atoms for the decoration of vacancies can be incorporated by plasma exposure or ion implantation.

Conversion Efficiency of Radiation Damage Profiles into Hydrogen-Related Donor Profiles

“…After implantation, the proton-implanted samples are annealed under inert atmosphere or in air (no difference between the different atmospheres is observed) at 470±10 °C for 5 h or 15 h. The post-implantation hydrogen-plasma exposures are realized with a Radio-Frequency setup operating at 13.56 MHz standard frequency providing a plasma power of 150 W. The plasma hydrogenations are carried out at 450±1 °C for either 15 min or 60 min (see Ref. [18] for more details).…”

(Invited) The Thermal Budget of Hydrogen-Related Donor Profiles: Diffusion-Limited Activation and Thermal Dissociation

“…The basic core complex evolves from crystal damage induced by the irradiation. Thus, such donor-like defect states may also be observed in samples irradiated with neutrons (5), electrons (6), or helium (7) if the hydrogen necessary for the decoration of the core complexes is provided -e.g., by in-diffusion from a hydrogen plasma source (7)(8)(9)(10). Depending on the temperature of the annealing step, different energy levels with ionization energies of several 10 meV were reported and associated with HDs (11)(12)(13)(14).…”

The Impact of Helium Co-Implantation on Hydrogen Induced Donor Profiles in Float Zone Silicon

“…The underlying defect species of the induced shallow donors are intrinsic point defect complexes (probably vacancy or multi-vacancy complexes) which are decorated with hydrogen, where the basic core complex evolves from crystal damage caused by the irradiation. Thus, such donor-like defect states may also be observed in samples irradiated with neutrons (5), electrons (6) or helium (7) if the hydrogen necessary for the decoration of the core complexes is provided -e. g., by indiffusion from a hydrogen plasma source (7)(8)(9)(10). Depending on the temperature of the annealing step, different energy levels with ionization energies of several 10 meV were reported and associated with the hydrogen-decorated intrinsic defect donor species (HDs) (5,(11)(12)(13).…”

“…During the successive annealing step, the implanted hydrogen diffuses through the silicon layer penetrated by the implantation and, depending on the annealing conditions, the donor profile may therefore fully develop toward the surface (14). In case of providing the necessary hydrogen by a plasma source at the surface of a float zone silicon sample with radiation damage introduced beforehand by light ion irradiation, it was found that an overexposure with hydrogen led to diminishing effective carrier concentrations in the sample (7)(8)(9)(10). When using proton implantation to create the HDs, the defects and the hydrogen are inserted simultaneously and, in contrast to the in-diffusion of the hydrogen from the plasma, the amount of introduced hydrogen is known and controllable.…”