Polymethylmethacrylate (PMMA) is a positive tone photoresist, which undergoes chain scission under extreme ultraviolet exposure and is often used as a model photoresist for mechanistic studies due to its simplicity. Nano projectile secondary ion mass spectrometry (NP-SIMS) can be used to gain chemical information about the surface composition of a sample. NP-SIMS involves the bombardment of the sample surface with primary ions and the collection of the ejected secondary ions. The primary ions, Au4004+, are separated in time and space, and this enables the analysis of the secondary ions from each individual impact. Thin films (≈25 nm thick) of spin-cast PMMA of different molecular weights (35, 200, 495, and 950 kDa) on the silicon substrate were investigated regarding postincident fragmentation patterns. Three circular areas of 125 μm diameter were analyzed, and a total of 1–1.5 × 106 spectra were taken for each sample.
The optical functions of crystalline paratellurite (alpha-TeO2) and amorphous TeO2 were determined using several optical techniques: (1) standard spectroscopic two-modulator generalized ellipsometry (2-MGE) of paratellurite (200-850 nm, 6.2-1.46 eV), (2) near-normal-incidence two-modulator generalized ellipsometry microscopy (2-MGEM) of paratellurite (577 nm, 2.15 eV), (3) Mueller matrix transmission of paratellurite (320-798 nm, 3.87-1.55 eV), and (4) polarized transmission of paratellurite (323.6-334.3 nm, 3.83-3.71 eV). The 2-MGE measurements yielded highly accurate values of the dielectric functions and error estimates from 1.46 to 6.2 eV for both paratellurite and amorphous TeO2, whereas the polarization-dependent transmission yielded more accurate values of the absorption coefficient below the band edge of paratellurite. The 2-MGEM measured the diattenuation of paratellurite, which is related to the birefringence. Mueller matrix transmission measurements of paratellurite of a (001) cut crystal as a function of angle of incidence were used to determine both the birefringence and the rotary power as a function of photon energy.
Monochromatic Al Kα (1486.6 eV) and monochromatic Cr Kα (5414.8 eV) radiation sources were used to acquire x-ray photoelectron spectroscopy (XPS) and hard x-ray photoelectron spectroscopy (HAXPES) data on bulk semimetallic HgTe. The reported spectra include survey scans, high-resolution core-level spectra of Hg and Te, and x-ray-excited Auger transitions. These data provide reference binding and kinetic energy values and are intended to support future XPS and HAXPES studies of HgTe and related materials.
Polymer coatings with tailored properties have enabled advances and innovations in industry, biomedicine, sensorics, and consumer goods. The optimization of the functionality and the development of new applications require the comprehensive characterization of the material properties. Along with other methods, time-of-flight secondary ion mass spectrometry is applied for this purpose. Here, we provide reference spectra for Teflon (TM) AF 1601, a soluble, amorphous fluoropolymer with applications in innovative fields such as opto-electronics, microfluidics, and sensorics. Spectra were measured with positive and negative polarity using a 30 kV Bi-3(++) primary ion beam.
Trimethylsilyl-functionalization via N-(trimethylsilyl)dimethylamine (TMSDMA) vapor exposure is used by the semiconductor industry to selectively passivate SiO2 surfaces during area selective deposition. Although the effectiveness of this molecule at inhibiting deposition has been studied, there have been very few published journal articles that include XPS analysis of this passivated SiO2 surface. In addition, none of these studies provide high-resolution deconvolution of the XPS peaks associated with the adsorbed siloxyl groups. To help rectify this, XPS was used to analyze coupons cleaved from a TMSDMA-treated, 5 nm plasma-oxidized SiO2/Si(100) wafer. High-resolution, angle-resolved XPS spectra of the Si 2p, C 1s, and O 1s core regions were collected at an emission angle of 80 degrees with respect to the surface normal. Initial attempts to analyze the functionalized surface revealed that the molecular films degrade rapidly during analysis. In order to mitigate degradation of the organic monolayer, single-scan measurement sets (Si 2p, C 1s, and then O 1s) were performed on 78 separate analysis spots, which limits the x-ray exposure time of the functional groups at each measurement spot to 3 min. The spectra were then averaged to produce the high-resolution narrow-energy core spectra of the Si 2p, C 1s, and O 1s regions. This analysis technique, in conjunction with the high surface sensitivity of the angle-resolved XPS measurements at an emission angle of 80 degrees, has made it possible to identify the O-Si(CH3)(3) and Si-CH3 chemical shifts within the Si 2p and C 1s regions, respectively.
