Modulated reflectance measurement system using UV probe

A method for evaluating a sample, the method comprising:

• focusing an intensity modulated pump beam on the sample surface to periodically excite a first measurement site;
• focusing an ultra-violet probe beam within the first measurement site;
• measuring the modulation imparted to the probe beam by the first measurement site;
• and
• tuning the wavelength of the probe beam to minimize the thermal wave contribution to the probe beam modulation.

A method for evaluating a sample, the method comprising:

• focusing an intensity modulated pump beam on the sample surface to periodically excite a first measurement site;
• focusing an ultra-violet probe beam within the first measurement site;
• measuring the modulation imparted to the probe beam by the first measurement site;
• and
• tuning the wavelength of the probe beam to vary the thermal and plasma wave contributions to the probe beam modulation.

A device for evaluating a sample, the device comprising:

• a first illumination source producing an intensity modulated beam for periodically exciting a region on the sample;
• a second illumination source producing a probe beam to reflect off the region on the sample surface that has been periodically excited where the probe beam has a spectral range selected from a group that includes:
• 395 to 410 nm and 355 to 365 nm;
• a detector for monitoring the modulated changes in the reflected probe beam and generating output signals in response thereto;
• and
• a processor for evaluating the sample using the detector output signals.

A device for evaluating a sample, the device comprising:

• a first illumination source producing an intensity modulated beam for periodically exciting a region on the sample;
• a second illumination source producing a probe beam to be reflected by the periodically excited region, where the probe beam has a wavelength within the UV range that corresponds to a local maxima of the temperature reflectance coefficient of the sample;
• a detector for monitoring the modulated changes in the reflected probe beam which and generating output signals in response thereto;
• and
• a processor for evaluating the sample by analyzing the detector output signals.

A device for evaluating a sample, the device comprising:

• a first illumination source producing an intensity modulated beam for periodically exciting a region on the sample;
• a second illumination source producing a probe beam to be reflected by the periodically excited region, where the wavelength of the probe beam is tunable to minimize the thermal wave contribution to the probe beam modulation;
• a detector for monitoring the modulated changes in the reflected probe beam which and generating output signals in response thereto;
• and
• a processor for evaluating the sample by analyzing the detector output signals.

A device for evaluating a sample, the device comprising:

• a first illumination source producing an intensity modulated beam for periodically exciting a region on the sample;
• a second illumination source producing a probe beam to be reflected by the periodically excited region, where the wavelength of the probe beam is tunable to equalize the thermal and plasma wave contributions to the probe beam modulation;
• a detector for monitoring the modulated changes in the reflected probe beam which and generating output signals in response thereto;
• and
• a processor for evaluating the sample by analyzing the detector output signals.