Formation and Properties of Copper Silicide Precipitates in Silicon

Abstract

We report results of a detailed study of structural and electrical properties of copper silicide precipitates in silicon. Using conventional and high‐resolution transmission electron microscopy we observe that metastable platelets surrounded by extrinsic stacking faults form upon quenching from high temperatures. By ripening experiments at low temperatures as well as by a variation of cooling rates it is shown how homogeneous copper precipitation merges into the heterogeneous precipitation mode of colony growth. The application of recently developed criteria for the interpretation of deep level transient spectra from extended defects allows to conclude that deep electronic states associated with the precipitates have bandlike character.

Filling the voids in silicon single crystals by precipitation of Cu3Si

“…If the cooling rate is low (<100 K/s), precipitate colonies bounded by extrinsic dislocation loops may form near the surface [3]. If the cooling rate is high (>1000 K/s), homogeneous precipitation accompanied by formation of stacking faults happens inside the Si crystal [11]. Therefore, slow cooling is preferred for Cu precipitation in the voids in order to avoid additional precipitates.…”

“…Among these metals, Cu has been studied intensively since Dash used it to decorate dislocations in silicon crystals [1]. Precipitation of Cu in silicon proceeds by formation of Cu silicide either heterogeneously at lattice imperfections, such as dislocations [1][2][3][4][5][6], stacking faults [7,8], and grain boundaries [9], or homogeneously in the silicon lattice [10,11]. The crystal structure of the precipitates examined in the transmission electron microscope (TEM) was reported to be the 00 -Cu 3 Si phase, in which the volume per Si atom is larger than in the silicon diamond cubic lattice [12].…”

“…The crystal structure of the precipitates examined in the transmission electron microscope (TEM) was reported to be the 00 -Cu 3 Si phase, in which the volume per Si atom is larger than in the silicon diamond cubic lattice [12]. Growth models of Cu 3 Si precipitates were therefore proposed based on a strain relaxation mechanism [11,13], such that Cu 3 Si nucleates at lattice imperfections that serve as vacancy sources or reduce the lattice strain. In recent transition-metal gettering technology, Cu precipitation in silicon cavities was observed as a monolayer formed on the cavity wall [14] or as a crystalline silicide *Corresponding author.…”

Energy level(s) of the dissociation product of the 1.014 eV photoluminescence copper center in n-type silicon determined by photoluminescence and deep-level transient spectroscopy

“…Since the Cu DLB center has no electrically active level in n-type silicon, 16 both PL and DLTS measurements are indispensable. Considering that the formation of extended defects which would lead to erroneous conclusions is easy in samples heavily diffused with copper at higher temperatures than 900 C, [17][18][19] it is important to use the samples diffused with dilute copper at lower temperatures than that temperature.…”

Modeling of light-induced degradation due to Cu precipitation in p-type silicon. I. General theory of precipitation under carrier injection

“…54,64,65 On the other hand, formation of spherical Cu precipitates has been reported on heterogeneous precipitation sites such as grain boundaries, dislocations (which can be induced by, e.g., oxygen precipitation), and stacking faults. 64,65 The Cu-LID defect has not been directly observed by microscopic methods, and therefore, the defect shape and type of nucleation (i.e., homogeneous vs. heterogeneous) remain inconclusive. In Cz samples with intentionally grown oxygen precipitates, Cu-LID has been shown to exhibit degradation behavior that can be interpreted to be characteristic of heterogeneous nucleation.…”