Growth by LPCVD, crystallization and characterization of SiGe nanoparticles for nanoelectronic devices

Abstract

Amorphous SiGe nanoparticles embedded in an oxide matrix, with controlled composition, diameter of a few nm, located in the same plane and with an areal density above 10 12 cm -2 have been deposited by Low Pressure Chemical Vapour Deposition in a single run using a conventional hot wall reactor. The deposited nanoparticles were crystallized by Rapid Thermal Annealing. X-ray Reflectometry and Rutherford Backscattering Spectrometry, with models developed for these purposes, have been tested as fast and reliable analytical tools to determine the composition, size and areal density of the nanoparticles. Transmission Electron Microscopy has been used to validate the results and to study the nanoparticle crystallization.

Optimization of the luminescence emission of Si nanocrystals synthesized from non-stoichiometric Si oxides using a Central Composite Design of the deposition process

“…The process parameters were selected based on our previous results on the deposition of stoichiometric oxides [4]. The pressure was varied between 185 and 300 mTorr and the temperature between 250 and 450 • C. The Si 2 H 6 /O 2 gas flow ratio was varied between 2 and 5 to ensure that the gas is rich enough in the precursor of Si.…”

Influence of the crystallization process on the luminescence of multilayers of SiGe nanocrystals embedded in SiO2

“…For these applications, the diameter of the nanoparticles should be uniform and of a few nanometers, and their spatial distribution must be regular and with a nanoparticle areal density above 5 × 10 11 cm −2 . SiGe nanocrystals, with controlled composition and size and the appropriate areal density, embedded in an oxide matrix have been obtained by low-pressure chemical vapor deposition (LPCVD) of amorphous discontinuous SiGe films followed by an annealing process to crystallize the nanoparticles [5]. These structures show luminescence emission with a main band peaking at a wavelength of 400 nm unambiguously associated to the presence of the crystallized nanoparticles * Corresponding author.…”

Structural stability of SiGe nanoparticles under ‘in situ’ electron beam irradiation in TEM

“…The samples deposition was carried out according to the procedures described elsewhere [1]. The crystallization of the nanoparticles was achieved by subsequent Rapid Thermal Annealing of the samples in N 2 atmosphere at 900 ºC for times of 60 s. The average density and diameter of the nanoparticles was 2 x10 12 cm -2 and 4 nm respectively and remain unchanged after crystallization.…”

“…The current densities were measured using a Gatan US 1000 CCD and are summarized in table 1. To obtain an estimation of the energy-loss, current densities measurements have been made with and without sample for the same beam conditions.…”

“…Previous results indicate that low pressure chemical vapour deposition (LPCVD) of amorphous discontinuous SiGe films embedded in SiO 2 and their subsequent crystallization permit to obtain a homogeneous distribution of SiGe nanocrystals fully compatible with CMOS technology [1].…”