V. V. Privezentsev

Nanoparticle process formation in zinc implanted silicon with followed thermal annealing

Results of temperature treatment effect on near surface layer properties of Zn ion implanted Si substrate are presented. Radiation induced point defects and Zn in depth profile was studied by Rutherford back scattering (RBS) method with use of channeling technique. Topology of substrate surface was studied by atomic force microscopy (AFM) and scaning electron microscope (SEM). Phase composition of samples was test by x-ray diffraction in grazing geometry.

ZnO Nanoparticle Formation in 64Zn+ Ion Implanted Al2O3

ZnO nanoparticles (NPs) formed in (-1012) sapphire substrates have been studied. The NPs were formed by implantation of 64Zn+ ions followed by furnace annealing in oxygen atmosphere for 1h at elevated temperatures. The radiation defects and Zn implant profiles were investigated by Rutherford backscattering spectroscopy of He+ ions with energy of 1.7MeV with scattering angle of 160o at Van de Graff accelerator using the ion channeling technique (RBS/CT). The surface morphology was studied by atomic force microscopy (AFM) and scan electron microscopy in secondary emission mode (SEM-SE). The distribution of Zn implant profiles was analyzed by secondary ion mass-spectrometry (SIMS). Identification of the phase content of the materials was carried out by X-ray photoelectron spectroscopy (XPS). In as implanted samples, a near-surface amorphization layer was formed, and in this layer the surface voids were created. After annealing in temperature range of 600-900°C the ZnO phase was synthesized in sapphire substrate. After annealing at 900°C one can see the phase variation from ZnO/Zn phases at sample surface to metal Zn phase in sample body at a depth of 40nm. Annealing at temperatures above 900°C leads to disappearing of ZnO phase and creating of ZnAl2O4 phase.

Formation of nanoparticles containing zinc in Si(001) by ion-beam implantation and subsequent annealing

The formation of nanoparticles containing zinc in Si(001) substrates by the implantation of 64Zn+ ions and subsequent annealing in dry oxygen at 800 and 1000°C for 1 h is studied. The structure of the samples is studied by high-resolution transmission electron microscopy, X-ray diffraction, and photoluminescence spectroscopy. 20-nm zinc nanoparticles located at a depth of about 50 nm are revealed in the as-implanted sample. 10–20-nm pores are observed in the surface layer. Annealing leads to oxidation of the Zn nanoparticles to the Zn2SiO4 state. It is shown that the oxidation of Zn nanoparticles begins on their surface and at an annealing temperature of 800°C results in the formation of nanoparticles with the “соre–shell” structure. The X-ray diffraction technique shows simultaneously two Zn and Zn2SiO4 phases. ZnO nanoparticles are not formed under the given implantation and annealing conditions.

Investigation of silicon doped by zinc ions with a large dose

The formation of nanoparticles in СZn-Si(100) implanted with 64Zn+ ions using a dose of 5 × 1016 cm–2 and an energy of 50 keV at room temperature with subsequent thermal processing in oxygen at temperatures ranging from 400 to 900°C is studied. The surface topology is investigated with scanning electron (in the secondary emission mode) and atomic force microscopes. The structure and composition of the near-surface silicon layer are examined using a high-resolution transmission electronic microscope fitted with a device for energy dispersive microanalysis. An amorphized near-surface Si layer up to 130 nm thick forms when zinc is implanted. Amorphous zinc nanoparticles with an average size of 4 nm are observed in this layer. A damaged silicon layer 50 nm thick also forms due to radiation defects. The metallic zinc phase is found in the sample after low-temperature annealing in the range of 400–600°C. When the annealing temperature is raised to 700°C, zinc oxide ZnO phase can form in the near-surface layer. The complex ZnO · Zn2SiO4 phase presumably emerges at temperatures of 800°C or higher, and zinc-containing nanoparticles with lateral sizes of 20–50 nm form on the sample’s surface.

Structure of Si near-surface layer after 64Zn+ ion implantation at elevated temperature

The results of studying the structure and composition of the surface layer of a Si plate after 64Zn+ ion implantation and thermal annealing in oxygen are presented. The ions are implanted into a substrate heated to a temperature of 400°C. Radiation defects and profiles of implanted Zn and oxygen diffused into the substrate are studied by means of 1.7-MeV He+-ion Rutherford backscattering spectroscopy using the channeling technique. The implanted layers are visualized using high-resolution transmission electron microscopy in combination with electron diffraction and energy dispersive microanalysis. Atomic-force microscopy is used to study the surface morphology.

Study of silicon implanted with zinc and oxygen ions via Rutherford backscattering spectroscopy

The structural features and dopant profiles of a Si surface layer implanted with Zn+ and O+ ions are studied via Rutherford backscattering spectroscopy based on the analysis of He2+-ion spectra with the use of the channeling technique. The doping-impurity redistribution is analyzed upon the formation of zinc-oxide nanoparticles. The sample surface morphology is examined by means of atomic-force microscopy and scanning electron microscopy under secondary-electron emission conditions. X-ray phase analysis of the implanted layers is carried out.

ZNO NANOPARTICLE CREATING IN A SIO2/SI STRUCTURE USING THE ZN ION IMPLANTATION WITH SUBSEQUENT HEAT TREATMENT

The distribution profiles of the dopant in the surface layer of a SiO2/Si structure implanted with Zn and O ions are studied via Rutherford backscattering spectroscopy for He2+ ions using the channeling technique. The redistribution of implanted impurities in the Si surface layer during the formation process of zinc oxide (ZnO) nanoparticles is analyzed. The effect of the annealing temperature on the formation process and growth of ZnO nanoparticles is studied. The sample-surface morphology is examined via atomic force microscopy. The optical absorption and photoluminescence of the implanted layers are studied.

ZnO Nanoparticle Formation in Si by Co-Implantation of Zn+ and O+ Ions

ZnO nanoparticles (NPs) formed in Czochralski-grown n-type (100) silicon substrates have been studied. The NPs were formed by co-implantation of 64Zn+ and 16O+ ions followed by furnace annealing in neutral/inert atmospheres for 1h. High-resolution transmission electron microscopy (HR TEM) of cross-section samples enabled the structural properties of the near surface layers to be characterized after implantation and annealing. The distribution of implant profiles was analyzed by secondary ion mass-spectrometry (SIMS). The surface morphology was studied by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Identification of the phase content of the materials was carried out by high-resolution X-ray diffraction in θ-2θ scanning mode. In as-implanted samples, a big amorphous layer was formed which destroyed the NPs beneath the surface. After furnace annealing from 600 up to 800°C, ZnO(102) NPs with a size of ~7nm were formed in the recrystallization layer. Furnace annealing at temperatures above 900 °C gave rise to a restructuring of the silicon surface and ZnO NPs formed on the sample surface. At temperatures above 1000 °C, out-diffusion of Zn from the sample occurred due to the large diffusion coefficient Zn at these temperatures.

Defect structure transformation after thermal annealing in a surface layer of Zn-implanted Si(001) substrates

A combination of high-resolution X-ray diffractometry, Rutherford back scattering spectroscopy and secondary-ion mass spectrometry (SIMS) allowed the influence of structural transformations in the damaged layer of Zn-doped Si(001) substrates after a multistage thermal treatment to be revealed. The shape of the Zn SIMS profiles correlates with the crystal structure of the layer and depends on the presence of factors influencing the mobility of Zn atoms.

Changes of structure and composition of a zinc ion-implanted silicon surface during nanoparticle formation upon thermal treatment

Data from investigating the formation of nanoparticles (NPs) on a surface of silicon wafers after zinc ion implantation and thermal annealing are presented. The investigation is conducted by means of trans-mission electron microscopy, electron diffraction analysis, energy dispersive microanalysis, scanning tunneling microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. It is found that on their surfaces, the implanted samples have only films of amorphous silicon containing implanted zinc, oxygen, and carbon contamination. Thermal treatment in the range of 400–800°C leads to the formation NP with 20–50 nm wide and 10 nm tall on a wafer’s surface, plus a silicon oxide layer about 20 nm thick. NPs are composed of zinc compounds of the ZnO, ZnSiO3, or Zn2SiO4 types. These NPs disappear after annealing at 1000°C.