Noncontact, in-line measurement of boron concentration from ultrathin boron-doped epitaxial Si1–xGex layers on Si(100) by multiwavelength micro-Raman spectroscopy

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To meet various physical property requirements of materials for advanced applications for specific devices, combinations of Si/Ge, Ge/Si, Si 1-x Ge x /Si, are frequently introduced in the device fabrication process. Epitaxy, condensation and annealing processes are commonly used. Since a small variation in composition, strain and crystallinity can result in reduced device performance or failure, the composition, strain and crystallinity must be carefully monitored and controlled throughout the manufacturing process. We have studied the dependence of Ge and Si intermixing on annealing temperature and Raman excitation wavelength. Using multiwavelength Raman spectroscopy, we found Ge and Si intermixing in epitaxially grown Ge(100)/Si(100) after successive thermal anneals. Very strong dependence of signal-to-noise (S/N) ratio measurements on excitation wavelength and film structure was observed. Suitable excitation wavelengths must be chosen to properly characterize Si and Ge-based heteroepitaxial layers based on the thickness, stacking order and composition of epitaxial films having different optical properties at different wavelengths.

Section: Resultsmentioning

confidence: 62%

Characterization of Hetero-Epitaxial Ge Films on Si Using Multiwavelength Micro-Raman Spectroscopy

Yoo¹,

Kang²,

Ueda³

et al. 2014

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“…Details of Ge content monitoring using Raman spectroscopy can be found in previous reports. [25][26][27][28][29][30][31][32][33][34] Raman characterization of intermixing between Si and Ge in epitaxial Ge on Si, Si/Ge core-shell nanowires and Si/Ge/Si core-double shell nanowires after annealing has been reported. [35][36][37][38] Figures 9-11 show multiwavelength (457.9 nm, 488.0 nm and 514.5 nm) excitation Raman spectra in the wavenumber range of 490 cm −1 ∼ 550 cm −1 covering the Si peak at ∼520 cm −1 and Si-Si peak of Si 1-x Ge x from as received TiN/Ni/Si 1-x Ge x /SiO 2 /Si with various Ge content.…”

Section: Resultsmentioning

confidence: 99%

Thermal Silicidation of Ni/SiGe and Characterization of Resulting Nickel Germanosilicides

Yoo¹,

Kang²,

Ishigaki³

et al. 2020

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Thermal silicidation characteristics of Ni/Si1-xGex with various Ge content was studied under different annealing temperatures in the range of 225 °C ∼ 400 °C in 100% N2 ambient. TiN capped Ni/Si1-xGex/Si/SiO2/Si wafers with x values in the range of 0.15 and 0.30 in 0.05 intervals were used. Thermal silicide formation was performed in a stacked hotplate-based annealing system designed for industrial 300 mm wafer fabs. For silicide characterization, measurements of spectral reflectance, sheet resistance, Raman spectra as well as X-ray diffraction curves were performed to investigate changes of optical properties, electrical properties, crystallographic phases during silicide formation. Effects of Ge content and annealing temperature on the electrical and crystallographic properties of the resulting thermal silicides (nickel germanosilicides) were investigated. Reaction mechanisms were discussed based on the characterization results. Multiwavelingth micro-Raman spectroscopy was found to be very promising as a non-contact, in-line silicidation process monitoring technique. For production worthiness verification of the thermal silicidation process, temperature sensitivity curves of sheet resistance, its uniformity and detailed sheet resistance maps were investigated using 8 nm thick Ni films on 300 mm diameter, epitaxial Si0.8Ge0.2/p−-Si wafers without a capping layer. Manufacturability of Ni/Si0.80Ge0.20/Si wafers were also verified using a stacked hotplate-based, nearly isothermal, annealing system.

“…The details of the system and its applications can be found in previous publications. [23][24][25] The excitation laser beam spot size was in the range of ∼0.5 μm in diameter. The laser power at the wafer surface was 5 mW to 20 mW.…”

Section: Methodsmentioning

confidence: 99%

“…28 By selecting appropriate excitation wavelengths for desired probing depths, variations in crystalline lattice quality can be examined. [23][24][25] Figure 10 shows 363.8 nm and 441.6 nm excited Raman spectra from all wafers, before and after plasma etching, under various TCP and bias RF power conditions, in groups, by type of wafers. Exposure time was kept constant for easy Raman signal intensity comparisons.…”

Section: Room Temperature Photoluminescence (Rtpl)-figuresmentioning

confidence: 99%

Visualization of Plasma Etching Damage of Si Using Room Temperature Photoluminescence and Raman Spectroscopy

Jian

Jeng

Wang

et al. 2013

Room temperature photoluminescence (RTPL) and Raman spectroscopy were used for characterizing plasma-induced-damage (PID) of Si during plasma assisted Si processing. Oxide films with thicknesses of ∼200 and ∼600 nm were grown on 300 mm wafers by plasma enhanced chemical deposition (PECVD). Bare Si wafers with native oxide and PECVD oxide films were plasma etched under different etching and bias radio frequency (RF) power conditions. Oxide etch rate, oxide uniformity and RTPL spectra/intensity were measured and characterized under three excitation wavelengths (532, 650 and 827 nm) with different probing depths. High spectral resolution Raman measurements were performed under various excitation wavelengths from the ultraviolet (UV) to visible (VIS) region to verify the distribution of plasma etching damage in the depth direction as a function of plasma etching condition and structure of specimens. A distinct pattern of PID, corresponding to showerhead patterns, common to a typical plasma etching system, was observed from RTPL wafer mapping results. Multiwavelength Raman characterization revealed that the physical damage to the Si crystalline lattice, from plasma etching, was concentrated at, or near, the Si surface and SiO 2 /Si interface. Identification and characterization of PID were successfully done by using multiwavelength RTPL and Raman spectroscopy.