Reduction of transient diffusion from 1–5 keV Si+ ion implantation due to surface annihilation of interstitials

Abstract

The reduction of transient enhanced diffusion (TED) with reduced implantation energy has been investigated and quantified. A fixed dose of 1×1014 cm−2 Si+ was implanted at energies ranging from 0.5 to 20 keV into boron doping superlattices and enhanced diffusion of the buried boron marker layers was measured for anneals at 810, 950, and 1050 °C. A linearly decreasing dependence of diffusivity enhancement on decreasing Si+ ion range is observed at all temperatures, extrapolating to ∼1 for 0 keV. This is consistent with our expectation that at zero implantation energy there would be no excess interstitials from the implantation and hence no TED. Monte Carlo modeling and continuum simulations are used to fit the experimental data. The results are consistent with a surface recombination length for interstitials of <10 nm. The data presented here demonstrate that in the range of annealing temperatures of interest for p-n junction formation, TED is reduced at smaller ion implantation energies and that this is due to increased interstitial annihilation at the surface.

Study on interfacial dislocations of Si substrate/epitaxial layer by self-interstitial decoration technique

“…Superlattice structures of successive layers of Si-and B-doped Si fabricated by MBE growth have advanced greatly the fundamental understanding of the interaction between defects-dopant in Si in last decade. [8][9][10][11] Recently, boron-doped superlattices were intensively used to study phenomena related to high-energy ion bombardment. 10,11 The interfacial trapping strongly modifies the concentration of defects when high-energy ion bombardment was involved.…”

“…This can be a crucial issue in the recent study of dopants-defect interaction that utilized MBE-grown materials exclusively as the target of ion bombardment. [8][9][10][11] In this study, a layer of Si was grown by MBE on Si͑100͒ p-type ͑2-4 ⍀ cm͒ substrates. The substrates were cleaned using a procedure previously described.…”

Study on Ultra Shallow Junction n-MOS with 350°C Microwave Annealing for Activation of Phosphorus Dopants in Germanium

“…The on/off current ratios and the subthreshold swing factors of devices after different annealing conditions are shown in Table (I). The device with two-step MWA (2P/75 s + 1.5P/300 s) shows very promising results, including the smallest S. S. factor (~ 900 mV/ dec), and the highest I on/off ratio (~2.6×10 1 …”

“…For future complementary metal-oxide semiconductor (CMOS) devices, scaling limiting becomes the main challenge, such as the formation of annealed ultra-shallow junctions (USJs) in the source/drain extension regions. The problems of transient-enhanced diffusion (TED) and electrical de-activation [1,2] are of particular concern. TED of n-type dopants may occur during annealing, causing the depth of ultra-shallow junctions to become deeper.…”

Recoil implantation method for ultrashallow p+/n junction formation

“…Surface proximity of the defects has been proposed as an important factor for defect annihilation during the anneal. [29][30][31] Therefore, TED may be alleviated in this recoil implantation method.…”