CMOS compatible 2T pixel for on-wafer in-situ EUV detection.

A novel 2-transistor (2T) pixel EUV detector is proposed and demonstrated by advanced CMOS technology. The proposed 2T detector also exhibits high spectral range (< 267 nm) and spatial resolution (67 µm) with high stability and CMOS Compatibility. The compact 2T EUV detector pixels arranged in a test array are capable of on-wafer recording the 2D EUV flux distribution without any external power. The compact 2T EUV detector pixels arranged in a test array are capable of on-wafer recording the 2D EUV flux distribution without any external power. Through proper initialization process, EUV induced discharging mechanism is fully investigated and an EUV induced electron emission efficiency model is established. Finally, a 2D array for in-situ EUV detection is demonstrated to precisely reflect the pattern projected on the chip/wafer surface.

Embedded Micro-detectors for EUV Exposure Control in FinFET CMOS Technology.

An on-wafer micro-detector for in situ EUV (wavelength of 13.5 nm) detection featuring FinFET CMOS compatibility, 1 T pixel and battery-less sensing is demonstrated. Moreover, the detection results can be written in the in-pixel storage node for days, enabling off-line and non-destructive reading. The high spatial resolution micro-detectors can be used to extract the actual parameters of the incident EUV on wafers, including light intensity, exposure time and energy, key to optimization of lithographic processes in 5 nm FinFET technology and beyond.

Micellar transitions in solvent-annealed thin films of an amphiphilic block copolymer controlled with tunable surface fields.

We investigated the response of symmetric poly(styrene-block-4vinylpyridine) P(S-b-4VP) diblock copolymer micelles to surface fields of variable strength at free surfaces and substrate interfaces when the micelles as spun were subjected to solvent annealing. Free surface interactions were controlled with solvent annealing in solvents of varied selectivity. On exposure to vapors of a solvent strongly selective for PS, the micelles retained their spherical shape but grew into cylindrical micelles or lamellar nanostructures via fusion on exposure to slightly selective or neutral solvent vapors. Giant 2D disks that completely wetted PS-grafted substrates resulted when spherical micelles were exposed to vapors of a highly selective solvent for P4VP. The interfacial interactions were controlled through subjecting them to UV/ozone (UVO) substrates initially coated with an end-grafted layer of short PS chains, with which the grafted PS chains became oxidized, degraded, or totally removed through UVO treatment for a controlled duration. When thin films were annealed in vapors of THF, the structural transition from spherical to cylindrical micelles depended on the interfacial field. On applying selective UVO exposure of optimal duration, we fabricated a substrate with two interfacial chemistries that promoted varied micellar species (spherical and cylindrical micelles) with a sharp boundary developed within thin films through solvent annealing for a controlled duration.

Structure and spectroscopic study of aqueous Fe(III)-As(V) complexes using UV-Vis, XAS and DFT-TDDFT.

Aqueous complexes between ferric (Fe(III)) and arsenate (As(V)) are indispensable for understanding the mobility of arsenic (As) in Fe(III)-As(V)-rich systems. In this study, aqueous Fe(III)-As(V) complexes, FeH2AsO42+ and FeHAsO4+, were postulated based on the qualitative analysis of UV-Vis spectra in both Fe(III)-As(V)-HClO4 and Fe(III)-As(V)-H2SO4 systems. Subsequently, monodentate structures were evidenced by Fe K-edge EXAFS and modeled as [FeH2AsO4(H2O)5]2+ and [FeHAsO4(H2O)5]+ by DFT. The feature band at ∼280 nm was verified as electron excitation chiefly from Fe-As-bridged O atoms to d-orbital of Fe in [FeH2AsO4(H2O)5]2+ and [FeHAsO4(H2O)5]+. The structural and spectral information of Fe(III)-As(V) complexes will enable future speciation analysis in Fe(III)-As(V)-rich system.

Depth-Profiling Electronic and Structural Properties of Cu(In,Ga)(S,Se)2 Thin-Film Solar Cell.

Utilizing a scanning photoelectron microscope (SPEM) and grazing-incidence X-ray powder diffraction (GIXRD), we studied the electronic band structure and the crystalline properties of the pentanary Cu(In,Ga)(S,Se)2 (CIGSSe) thin-film solar cell as a function of sample depth on measuring the thickness-gradient sample. A novel approach is proposed for studying the depth-dependent information on thin films, which can provide a gradient thickness and a wide cross-section of the sample by polishing process. The results exhibit that the CIGSSe absorber layer possesses four distinct stoichiometries. The growth mechanism of this distinctive compositional distribution formed by a two-stage process is described according to the thermodynamic reaction and the manufacturing process. On the basis of the depth-profiling results, the gradient profiles of the conduction and valence bands were constructed to elucidate the performance of the electrical properties (in this case, Voc = 620 mV, Jsc = 34.6 mA/cm(2), and η = 14.04%); the valence-band maxima (VBM) measured with a SPEM in the spectroscopic mode coincide with this band-structure model, except for a lowering of the VBM observed in the surface region of the absorber layer due to the ordered defect compound (ODC). In addition, the depth-dependent texturing X-ray diffraction pattern presents the crystalline quality and the residual stress for each depth of a thin-film device. We find that the randomly oriented grains in the bottom region of the absorber layer and the different residual stress between the underlying Mo and the absorber interface, which can deteriorate the electrical performance due to peeling-off effect. An anion interstitial defect can be observed on comparing the anion concentration of the elemental distribution with crystalline composition; a few excess sulfur atoms insert in interstitial sites at the front side of the absorber layer, whereas the interstitial selenium atoms insert at the back side.