The Effect of Lattice Damage and Annealing Conditions on the Hyperfine Structure of Ion Implanted Bismuth Donors in Silicon

Abstract

This study reports on high energy bismuth ion implantation into silicon with a particular emphasis on the effect that annealing conditions have on the observed hyperfine structure of the Si:Bi donor state. A suppression of donor bound exciton, D0X, photoluminescence is observed in implanted samples which have been annealed at 700 °C relating to the presence of a dense layer of lattice defects that is formed during the implantation process. Hall measurments at 10 K show that this implant damage manifests itself at low temperatures as an abundance of p‐type charge carriers, the density of which is observed to have a strong dependence on annealing temperature. Using resonant D0X photoconductivity, we are able to identify the presence of a hyperfine structure in samples annealed at a minimum temperature of 800 °C; however, higher temperatures are required to eliminate effects of implantation strain.

Spin-Resonance Linewidths of Bismuth Donors in Silicon Coupled to Planar Microresonators

“…Far from the clock transition, the measurements from the 3D resonator match well with the results from the microresonators, while at the 7.3 GHz clock transition a linewidth of approximately 0.5 MHz is seen, equivalent to a HWHM in A of 0.1 MHz, enabling Si isotope shifts to be resolved (see the Supplemental Material [22]). The difference in the distribution of hyperfine couplings from bulk-doped Si and the ionimplanted samples studied here could be caused either by the 100× higher bismuth-donor concentration and/or residual strain from ion implantation [20]. For spins in silicon beneath patterned microresonators, strain is known to arise from the different coefficients of thermal expansion (CTEs) of the various materials.…”

“…1(b)]. Samples are annealed at 900 • C for 5 min to incorporate the bismuth atoms into the silicon lattice, forming spin-active donors with an efficiency of approximately 60% [20]. We place the resonators inside a copper 3D box in a setup similar to that used in Ref.…”

Using non-homogeneous point process statistics to find multi-species event clusters in an implanted semiconductor

“…As these specifics are dependent on the species and target of interest we leave possible simplifications to the reader. It has been shown previously that Bi implanted at a high energy into silicon (therefore creating many lattice defects) can be electrically activated to a high enough quality that the donor electron spin states are measurable [16]. This demonstrates the feasibility of ion implantation as the means creating the qubits of interest here.…”

Reducing strain in heterogeneous quantum devices using atomic layer deposition

“…We fabricated composite devices where a silicon substrate is ion implanted by Bi + at a density of ∼10 17 cm −3 in the top ∼ 1 µm before being annealed for 5 mins at 900 • C [19]. It is then coated by a 50 nm layer of Al 2 O 3 deposited at 150 • C by ALD immediately after RCA cleaning.…”