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

Abstract

Doping profiles in proton and helium co-implanted and annealed n-type float zone silicon wafers are analyzed by means of spreading resistance measurements. After annealing at sufficiently high temperatures and/or long-enough duration, the hydrogen-related donor profiles known from proton implantations are significantly enhanced by the helium irradiation. The resulting profile shape exhibits a strong resemblance to the radiation damage distribution of the co-implantation. By increasing the ultimately introduced number of hydrogen related donors without varying the available amount of hydrogen, it is shown that the donor profile resulting from proton implantation and annealing is limited by the defect species and the implanted hydrogen is supplied in surplus. The maximum of the additionally induced donor distribution by the helium implantation shows a different dependency on the fluence compared to the donor maximum induced by mere proton irradiation. The diffusion of the implanted protons through the irradiated layer during annealing is clearly impacted by the helium irradiation.

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

“…The concentration of the proton-induced HDs using fluences between 3×10 13 cm -2 and about 1×10 15 cm -2 is a non-trivial function of the proton fluence and the annealing temperature. The HD concentration depends linearly on the proton fluence for successive anneals at temperatures around 350 °C, whereas after annealing at temperatures around 470 °C a square-root dependence of the HD concentration on the fluence is observed (15,16). This behavior may be explained qualitatively by the appearance of two different types of HDs in the proton-implanted samples.…”

“…The depth distribution of the HDs is, in the initial stages of the activation, limited by the spatial overlapping of the radiation damage regions and the hydrogen distributions in the irradiated silicon (17). The total amount of HDs that may be activated in proton-implanted silicon is proven to be limited by the radiation-induced damage (16). I.e., the average amount of HD core complexes induced per implanted proton, with energies in the range of up to several MeV, is far less than one.…”

Activation and Dissociation of Proton-Induced Donor Profiles in Silicon

“…The HD concentration depends linearly on the proton fluence for successive anneals at temperatures around 350 • C, whereas after annealing at temperatures around 470 • C a square-root dependence of the HD concentration on the fluence is observed. 19,20 This behavior may be explained qualitatively by the appearance of two different types of HDs in the proton-implanted samples. These two species each exhibit a different proportionality to the implanted proton fluence.…”

“…While the z E-mail: johannes.laven@infineon.com former species disappears at annealing temperatures of about 400 • C, the later species remains stable up to annealing temperatures around 470 • C. 21 The depth distribution of the HDs is, in the initial stages of the activation, limited by the spatial overlapping of the radiation damage regions and the hydrogen distributions in the irradiated silicon. 20,21 The total amount of HDs that may be activated in proton-implanted silicon is proven to be limited by the radiation-induced damage 20 -i.e., the average amount of HD core complexes induced per implanted proton, with energies in the range of up to several MeV, is far less than one. The surplus hydrogen potentially has an even detrimental effect on the amount of induced HDs.…”

Thermal Budget of Hydrogen-Related Donor Profiles - Diffusion Limited Activation and Thermal Dissociation

“…Proton-induced doping profiles offer a feasible method for tailoring the carrier distribution in depths beyond 100 µm at proton energies of several MeV [1,2]. The donors used by this method are a radiation defect complex decorated by hydrogen.…”