Indium transient enhanced diffusion

Abstract

Indium, an acceptor dopant in silicon, is a large atom with a low diffusion coefficient potentially suitable for doping the channel of transistors. Systematic experiments are described which measure the susceptibility of indium to transient enhanced diffusion caused by ion implant damage introduced during the transistor fabrication process. We find that indium diffusion is dramatically enhanced by a source of interstitials and that the amount of enhancement is comparable to that seen for boron. Indium is preferable as a channel dopant not because of its diffusion behavior, but rather because a narrow ion implanted distribution can be obtained using the heavy indium ion, giving a more steeply retrograde profile than can be achieved by boron doping. These results help clarify the physics of indium and boron doping in small devices.

Defect suppression of indium end-of-range during solid phase epitaxy annealing using Si1−yCy in silicon

“…Between the increasing temperatures of 650-800 -C, the indium profile at the tail end remains stationary (between 90 and 200 nm depth); indicating that indium TED is suppressed. Considering that indium diffusion is enhanced by an interstitial mechanism [16], the diffusion profile further indicates a reduction in the concentration of silicon interstitials. When a graphical integration was performed to the SIMS profile, no dose loss was observed.…”

Indium penetration through thermally grown silicon oxide

“…The intrinsic diffusion parameters of indium in silicon are well established [3]. TED of indium in silicon was also investigated [5,12]. However, there was no information about the diffusion of indium in polycrystalline silicon.…”

“…For the samples with indium implantation into the silicon substrate, implantation damage generated excess interstitials. Such excess interstitials promoted indium diffusion, causing transient enhanced diffusion (TED) [5,12]. TED caused some indium atoms to migrate from the silicon substrate into the thin oxide.…”

Investigation of indium diffusion in strained silicon by ab initio calculation

“…1 Due to its heavier mass, indium is considered a good alternative to boron as a p-dopant in silicon for achieving the shallower and steeper profiles required for ultra-largescale integration (ULSI). 2,3 Strain effects on dopant diffusion have recently attracted a great deal of attention because strained silicon techniques have become a very popular method for enhancing the mobility of carriers in next-generation metal oxide semiconductor field effect transistors. 4 As ULSI devices approach nanoscale dimensions, heavy ion implantation and induced strain methods are becoming increasingly important, and studies of the properties of indium diffusion in strained silicon will aid in the development of successful process integration.…”