Enhanced electrical activation in In-implanted Ge by C co-doping

Abstract

At high dopant concentrations in Ge, electrically activating all implanted dopants is a major obstacle in the fulfillment of high-performance Ge-channel complementary metal oxide semiconductor devices. In this letter, we demonstrate a significant increase in the electrically-active dopant fraction in In-implanted Ge by co-doping with the isovalent element C. Electrical measurements have been correlated with x-ray absorption spectroscopy and transmission electron microscopy results in addition to density functional theory simulations. With C þ In co-doping, the electrically active fraction was doubled and tripled at In concentrations of 0.2 and 0.7 at. %, respectively. This marked improvement was the result of C-In pair formation such that In-induced strain in the Ge lattice was reduced while the precipitation of In and the formation of In-V clusters were both suppressed. V

Enhanced Electrical Activation in In-Implanted Si0.35Ge0.65 by C Co-Doping

“…This is responsible for the relatively low In electrically active fraction (40.2%), given that In metal precipitation was not found in the sample. C-In pair formation as well as its similar effects on In solid solubility and electrical activation enhancement were observed in both C + In co-doped Si [3,[11][12][13] and Ge, [14][15][16] consistent with our results here with Si 0.35 Ge 0.65 . At the highest In concentration of 0.6 at%, In metal precipitation was found in both the In-implanted (Figure 2(a)) and C + In co-implanted (Figure 2(b)) samples.…”

“…Co-doping C with In is one of the most promising approaches to meet such a requirement. It has been reported that in both Si [3,[11][12][13] and Ge, [14][15][16] enhancement of In electrical activation was realized by C co-doping. Above-equilibrium solid solubility was attained in both substrates as a consequence of C-In pair formation that suppressed In precipitation.…”

Predicting band offset of lattice matched ZnO and BeCdO heterojunction from first principles

“…Some advanced methods such as GW [25] and hybrid functional [26] can yield correct band gap but require huge calculation cost which are hard to calculate heterojunctions involving around hundred atoms or more. Next, the calculations of semiconductor with impurities [27] also increase the calculation cost, especially when the concentration of one species is very small, because one needs to compute systems with a large number of host atoms to accommodate the impurities and to take configuration average over many calculations to obtain a more reliable physical result. Thirdly, transport property is crucial for heterojunction and related devices.…”

Electrical and Structural Properties of In and In + C Doped Ge

“…Further increasing the atomic concentration only leads to the formation of larger In particles with a cuboctahedron shape. Finally, it is important to note that even for the highest implantation fluence no In related nanoparticles were observed in the In + C doped system [3,4].…”