No abstract

In this work, a series of 13 boron implants were performed into Czochralski silicon substrates with doses of 2ϫ10 14-1.6ϫ10 15 cm Ϫ2 at energies of 10-80 keV. The boron was deliberately clustered with a 750°C anneal of 10 or 30 min and the electrical activation of the boron implants was determined following a second anneal at 750 or 850°C with a Hall effect system with certain samples also being analyzed with a spreading resistance technique. Analysis of the reactivation rates allows for the determination of the net energy to boron reactivation to be approximately 3.0 eV assuming the reactivation process is mediated by release of a boron interstitial with a migrational energy of 0.3 eV. This results in a critical binding energy of approximately 2.7 eV from the process limiting the dissolution of the most stable boron-interstitial cluster.

No abstract

Low temperature molecular beam epitaxy was used to grow boron doping superlattices DSLs in Si, with peak boron concentrations of 110 18 /cm 3 , and spike widths of 10 nm. Amorphization of these DSLs was achieved using a series of Si implants of 30 and 112 keV, each at a dose of 1 10 15 /cm 2 , which placed the amorphous to crystalline interface between the first and second doping spikes. The dose rate of the Si implants was varied from 0.13 to 1.13 mA/cm 2. Post-implantation anneals were performed in a rapid thermal annealing furnace at 800°C, for times varying from 5 s to 3 min. Secondary ion mass spectrometry was used to monitor the dopant diffusion after annealing. Increasing the implant dose rate appears to increase the amount interstitial flux toward the surface but has no observable effect on the flux into the crystal. Transmission electron microscopy was used to study the end of range defect evolution. Increasing dose rate was observed to decrease the end of range defect density. These observations are consistent with previous findings that indicate the amount of backflow toward the surface decreases as the end of range loop density increases.

A physically-based continuum diffusiodclustering model has been applied to the simulation of transient activationheactivation of ion implanted boron. This work is aimed at the optimization and development of post-implant thermal cycles for minimal dopant diffusion with peak activation. This model has been successfully applied to the simulation of several new structures exhibiting partial deactivation of the implanted boron.source/drain regions of MOS devices. Further work with this full cluster system has shown , for a range of conditions, that several of the boron cluster species are in or near equilibrium with one another. This observation has allowed for the reduction of the full system to a system of three different boron clusters, while still maintaining virtually all of the physics inherent to this modeling approach. Details of these systems are shown in Figures 2 and 3. This reduced version of the model incorporating charge state effects is shown capable of accurately modeling diffusion and activation over a range of boron concentrations and anneal temperatures.