35 results about "Free carrier absorption" patented technology

A thermal processing apparatus and method in which a first laser source, for example, a CO2 emitting at 10.6 μm is focused onto a silicon wafer as a line beam and a second laser source, for example, a GaAs laser bar emitting at 808 nm is focused onto the wafer as a larger beam surrounding the line beam. The two beams are scanned in synchronism in the direction of the narrow dimension of the line beam to create a narrow heating pulse from the line beam when activated by the larger beam. The energy of GaAs radiation is greater than the silicon bandgap energy and creates free carriers. The energy of the CO2 radiation is less than the silicon bandgap energy so silicon is otherwise transparent to it, but the long wavelength radiation is absorbed by the free carriers.

The invention discloses a gradually doped wide waveguide interband cascade laser and a preparation method thereof, wherein the gradually doped wide waveguide interband cascade laser comprises: a substrate; Layer, lower respectively confinement layer, cascade region, upper respectively confinement layer, upper waveguide cladding, and upper contact layer; wherein, the thickness of the lower respectively upper confinement layer is on the order of hundreds of nanometers to microns, and the lower respectively Both the confinement layer and the upper confinement layer are gradually doped, so that the doping concentration at both ends of the lower confinement layer and the upper confinement layer is relatively high, and the doping concentration in the central region is relatively low. The graded doped wide waveguide interband cascade laser effectively improves the optical confinement factor and increases the optical gain; effectively reduces the voltage drop on the heterojunction surface, improves the photoelectric efficiency, reduces free carrier absorption, and reduces the loss of the device ; And can reduce the operating voltage, improve work efficiency.

The invention discloses a high-wavelength antimonide semiconductor laser structure, which belongs to the field of epitaxial structures made from novel materials for semiconductor lasers and aims at the problems and shortcomings that the power, efficiency and the like of an antimonide laser are lowered along with the increasing of wavelengths. The laser structure can alleviate the problem that thepower and efficiency of the laser are lowered due to free charge carrier absorption and the like, has the characteristics of low optical mode loss, strong cavity restrictions, low internal loss, highquantum well laser structure efficiency and the like, and can improve the performance of the antimonide laser such as the power, the efficiency and the like.

The invention is a semiconductor material property measurement device and method based on double probe beam for measuring the characteristic parameters of semiconductor materials and monitoring the doping process. It obtains the free carrier absorption signal and the light-modulated reflecting signal simultaneously in the same set of test system based on the absorption of the exciting light of theperiodic intensity modulation by the semiconductor materials; it obtains the free carrier absorption signal and light-modulated reflecting signal of the frequency domain by changing the modulation frequency of the exciting light; it obtains the free carrier absorption signal and light-modulated reflecting signal of the spatial domain by changing the spacing between the exciting light and the probe light; it may obtain the characteristic parameters of semiconductor materials and the process parameters as the doping concentration through the analysis and processing of the signals obtained or the comparison with the signal data of the calibration sample. The invention makes up for the shortcomings of the single technology and improves the measurement accuracy; it obtains two kinds of signalssimultaneously in one device and more important parameters of the semiconductor materials comparing with the single technology.