Исследование морфологии поверхности и химического состава кремния, имплантированного ионами меди

This paper presents the results of studies of the structure and chemical composition of the surface of single-crystal silicon c-Si substrates implanted with Cu^+ ions with an energy of 40 keV and doses in the range of 3.1 · 10^15 - 1.25 · 10^17 ions/cm^2 at a current density in the ion beam of 8 μA/cm^2. Using scanning electron and probe microscopy in combination with X-ray photoelectron and Auger electron spectroscopy it was found that at the initial stage of irradiation with Cu^+ ions up to a dose of 6.25 · 10^16 ions/cm^2 Cu metal nanoparticles with an average size of 10 nm are formed in the surface layer of Si. With a further increase in the implantation dose starting from a value of 1.25 · 10^17 ions/cm^2 and higher the η-phase of copper silicide η-Cu3Si nucleates. This circumstance is due to the heating of the near-surface layer of Si substrate during its irradiation to a temperature conducive to the phase formation of η-Cu3Si.

Формирование нанопористых пленок силицидов меди

The possibility of forming nanoporous copper-silicide films with different phase compositions is experimentally demonstrated. For this purpose, the parameters of the initial a -Si/Cu structure and the conditions of its annealing are chosen so that the process of solid-phase synthesis comes to a halt at the stage of formation of a branched silicide cluster. Then the films are subjected to liquid etching in a mixture of diluted inorganic acids. In this case, the metastable Cu_ x Si phase with a low Cu content is selectively removed, and a three-dimensional silicide cluster is released. At the same time, surface Kirkendall voids present in the films open. As a result of these two processes in combination, a nanoporous structure is formed.

Структурные изменения в пленках Si-CuSi при интеркаляции ионов лития

Films of amorphous silicon reinforced with crystalline copper silicide inclusions were tested as anode material in liquid lithium-ion cells. The films were made by the method of layer-by-layer magnetron deposition of amorphous silicon and copper, followed by low-temperature (100 ÷ 200 ° C) annealing of the structure. During the tests, the anodes revealed the effect of long-term intensive growth of their reversible capacity. To describe the effect, a phenomenological model is proposed, based on the counter-migration of silicon and copper atoms in a non-uniform field of elastic mechanical stresses arising during the cycling of a lithium-ion cell.