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We demonstrate the broadband visible luminescence from bulk crystalline silicon and silicon nanoparticles sized 100- 30 nm under near-infrared excitation. We show that the luminescence spectrum has two distinct peaks. The first being centered at 550 nm while the second appears close to the wavelength of the second harmonic of the excitation light. The appearance of the second peak is a signature of the highly athermal electron distribution never observed previously. The luminescence intensity and spectral shape strongly depend on the doping type and concentration. Despite being nonresonant, silicon nanoparticles enhance luminescence intensity when placed atop the silicon wafer. The observed phenomenon can be used for wafer inspection and defect detection, as well as for the creation of novel nanosources of light.

We present a novel optical device which interchanges two orthogonal directions in the cross-section of a beam. The optical prism is composed of six flat faces and has particular edge angles. The beam passing through the component is totally reflected at right angles inside the prism and flipped diagonally at the exit with respect to the entrance. When a line beam is incident to the device, the beam is segmented step by step at the first side face and combined on the other side. The overall shape of the line beam is maintained at the exit, but the segments of the line beam are flipped. The narrow axis of the line beam at the exit has the divergence angle corresponding to the long axis at the entrance. The component is also useful to focus beams from linear laser diode array with asymmetric divergence angles. Compared to the other beam transformation systems, the suggested device has advantages of easy fabrication, coating-free and no energy loss on reflective surfaces.

Advances in the semiconductor industry have led the wafer inspection technology to the limit of nanometer-scale defect detection, which is far beyond the diffraction limit. In this regime, the signal-to-noise ratio (SNR) is the figure-of-merit to determine whether the optical system can detect a single nanometer-scale defect. In this paper, we investigated the SNR properties of various line defects using the dark-field inspection with tailored polarized illumination by simulation and experiment. Conventional crossed Nicols configuration with linear polarized illumination and crossed analyzer can minimize background scattering noise and maximize line defect signal only for a specific kind of line defect such as gap or bridge due to strong polarization dependence on a line and space (L/S) pattern. The nulling elliptically polarized illumination is optimized to suppress background scattering noise moderately and maintain defect signal intensity at the same time. We confirmed SNR improvement for both 10 nm open and bridge defects on 40 nm line and space silicon pattern with 40 nm depth. There was a good agreement between our simulation results and experimental results. We experimentally confirmed SNR ~ 4 for both line gap and bridge defect detection on 40 nm L/S patterned wafer with the fixed nulling illumination.

Detection of a single nanoparticle on a bare silicon wafer has been a challenge in the semiconductor industry for decades. Currently, the most successful and widely used technique is dark-field microscopy. However, it is not capable of detecting single sub-10 nm particles owing to a low signal-to-noise ratio (SNR). As a new approach, we suggest using the second harmonic generation (SHG) to detect a single nanoparticle. The second harmonic generation in centrosymmetric materials, like silicon, is forbidden except for a thin and additionally increase local field factors, allowing for their persistent detection. Choosing the proper surface and increasing SNR. We demonstrate the feasibility of the nonlinear dark-field microscopy concept by detecting an isolated 80-nm silicon nanoparticle on the silicon wafer.