Method and apparatus for measuring the concentration of ions implanted in semiconductor materials

A method for determining a concentration of ions implanted in a material, comprising the steps of:

• generating a single laser pulse;
• passing the single laser pulse through a phase mask to form at least two excitation sub-pulses and at least one probe pulse;
• irradiating a region of the material with a grating pattern, formed by overlapping the at least two excitation least sub-pulses to initiate a time-dependent response in the region;
• diffracting the probe pulse off the region to generate at least one time-dependent signal beam;
• detecting the at least one time-dependent signal beam to generate a signal waveform;
• and
• processing the signal waveform to determine the concentration of ions implanted in the material.

An apparatus for determining a concentration of ions implanted in a semiconduting material, comprising:

• a laser for generating an excitation laser pulse and a probe laser pulse from a single laser pulse;
• a first beam-delivery system for separating the excitation laser pulse into at least two excitation sub-pulses and then irradiating a region of the material with a grating pattern formed by overlapping the at least two excitation sub-pulses to initiate a time-dependent response in the region;
• a second beam-delivery system for delivering the probe pulse to the sample such that the probe pulse diffracts off the region to generate a time-dependent signal beam;
• a photodectector for detecting the time-dependent signal bean to generate a signal waveform;
• and
• a processor for processing the signal waveform to determine the concentration of ions implanted in the material.

An apparatus for determining a concentration of ions implanted in a semiconducting material, comprising:

• a laser for generating a single laser pulse;
• a beam-delivery system comprising a phase mask that separates the single laser pulse into at least two excitation sub-pulses and a probe pulse, and a lens that focuses and overlaps at least two excitation sub-pulses and the probe pulse on the sample so that the excitation sub-pulses form a grating pattern that initiates a time-dependent response in the region and the probe pulse diffracts off the region to generate a time-dependent signal beam;
• a photodetector for detecting the time-dependent signal beam to generate a signal waveform;
• and
• a processor for processing the signal waveform to determine the concentration of ions implanted in the material.