Abstract:
A high sensitivity image sensor comprises an epitaxial layer of silicon that is intrinsic or lightly p doped (such as a doping level less than about 1013 cm−3). CMOS or CCD circuits are fabricated on the front-side of the epitaxial layer. Epitaxial p and n type layers are grown on the backside of the epitaxial layer. A pure boron layer is deposited on the n-type epitaxial layer. Some boron is driven a few nm into the n-type epitaxial layer from the backside during the boron deposition process. An anti-reflection coating may be applied to the pure boron layer. During operation of the sensor a negative bias voltage of several tens to a few hundred volts is applied to the boron layer to accelerate photo-electrons away from the backside surface and create additional electrons by an avalanche effect. Grounded p-wells protect active circuits as needed from the reversed biased epitaxial layer.
Abstract:
A method of inspecting a sample at high speed includes directing and focusing radiation onto a sample, and receiving radiation from the sample and directing received radiation to an image sensor. Notably, the method includes driving the image sensor with predetermined signals. The predetermined signals minimize a settling time of an output signal of the image sensor. The predetermined signals are controlled by a phase accumulator, which is used to select look-up values. The driving can further include loading an initial phase value, selecting most significant bits of the phase accumulator, and converting the look-up values to an analog signal. In one embodiment, for each cycle of a phase clock, a phase increment can be added to the phase accumulator. The driving can be performed by a custom waveform generator.
Abstract:
A laser for generating an output wavelength of approximately 193.4 nm includes a fundamental laser, an optical parametric generator, a fourth harmonic generator, and a frequency mixing module. The optical parametric generator, which is coupled to the fundamental laser, can generate a down-converted signal. The fourth harmonic generator, which may be coupled to the optical parametric generator or the fundamental laser, can generate a fourth harmonic. The frequency mixing module, which is coupled to the optical parametric generator and the fourth harmonic generator, can generate a laser output at a frequency equal to a sum of the fourth harmonic and twice a frequency of the down-converted signal.
Abstract:
Methods and systems for minimizing interference among multiple illumination beams generated from a non-uniform illumination source to provide an effectively uniform illumination profile over the field of view of an inspection system are presented. In some examples, a pulsed beam of light is split into multiple illumination beams such that each of the beams are temporally separated at the surface of the specimen under inspection. In some examples, multiple illumination beams generated from a non-uniform illumination source are projected onto spatially separated areas on the surface of the specimen. A point object of interest illuminated by each area is imaged onto the surface of a time-delay integration (TDI) detector. The images are integrated such that the relative position of the illumination areas along the direction of motion of the point object of interest has no impact on the illumination efficiency distribution over the field of view.
Abstract:
A deep ultra-violet (DUV) continuous wave (CW) laser includes a fundamental CW laser configured to generate a fundamental frequency with a corresponding wavelength between about 1 μm and 1.1 μm, a third harmonic generator module including one or more periodically poled non-linear optical (NLO) crystals that generate a third harmonic and an optional second harmonic, and one of a fourth harmonic generator module and a fifth harmonic generator. The fourth harmonic generator module includes a cavity resonant at the fundamental frequency configured to combine the fundamental frequency with the third harmonic to generate a fourth harmonic. The fourth harmonic generator module includes either a cavity resonant at the fundamental frequency for combining the fundamental frequency with the third harmonic to generate a fifth harmonic, or a cavity resonant at the second harmonic frequency for combining the second harmonic and the third harmonic to generate the fifth harmonic.
Abstract:
A photomultiplier tube includes a semiconductor photocathode and a photodiode. Notably, the photodiode includes a p-doped semiconductor layer, an n-doped semiconductor layer formed on a first surface of the p-doped semiconductor layer to form a diode, and a pure boron layer formed on a second surface of the p-doped semiconductor layer. A gap between the semiconductor photocathode and the photodiode may be less than about 1 mm or less than about 500 μm. The semiconductor photocathode may include gallium nitride, e.g. one or more p-doped gallium nitride layers. In other embodiments, the semiconductor photocathode may include silicon. This semiconductor photocathode can further include a pure boron coating on at least one surface.