35 results about "Free carrier absorption" patented technology

A method for measuring semi-conductor doping density is characterized in that photocarrier radiometric technique and free carrier absorption measurement technique are integrated in a measurement system for simultaneously obtaining the complex radiation signal and absorption signal of the free carrier; the carrier radiation signal and absorption signal of a frequency domain are obtained through varying the modulating frequency of exciting light; the carrier radiation signal and absorption signal of a space domain are obtained through varying the distance between the exciting light and detecting light; and the doping density of the sample to be measured is obtained through comparing with the carrier radiation signal and absorption signal of a standard sample. The invention is based on photocarrier radiometric technique and free carrier absorption measurement technique, and integrates the information of two independent paths in respect frequency domain and space domain, so as to remarkably improve the measurement accuracy of doping density.

The invention discloses a semiconductor material characteristic measuring device and a method thereof which are used for measuring characteristic parameters of the semiconductor material and evaluating the processing quality of the material. In a test system, a light carrier radiation measuring signal, a free carrier absorption measuring signal and a light modulation reflection measuring signal of a sample can be simultaneously or respectively obtained just by an exciting light and a probe light. Light carrier radiation, free carrier absorption and light modulation reflection signal data are simultaneously or respectively analyzed and processed to obtain the characteristic parameters of the semiconductor material; when the data are compared with signal data of a standard or calibration sample, parameters of impurity concentration, defect concentration, and the like which are introduced during the processing of the semiconductor material can be measured.

This invention relates to one semiconductor mixture contraction measurement method based on freedom load flow absorption technique, which is characterized by the following: using one beam of photon with energy larger than the continuous laser with light intensity modulation of forbidden band as pump light source; using another beam of light smaller than semiconductor forbidden band width as detector light source; two beams of light are lighting onto same or adjacent positions on semiconductors; the semiconductor absorbs pump light to generate modulation free load flow; due to modulation free load flow absorbing through semiconductor or reflection detector light intensity by lock phase type or reflection detecting light signals for once resonance vibration and phase to get the mixture concentration.

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 the periodic 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 signals simultaneously in one device and more important parameters of the semiconductor materials comparing with the single technology.

The present invention provides a vertical cavity surface emitting laser and a manufacturing method thereof. The vertical cavity surface emitting laser comprises a substrate, a buffer layer, a lower DBR, an active layer, a current limiting aperture, a current diffusion layer, an undoped suspension type HCG layer, an n side electrode and a p-side electrode. The material extension difficulty of the vertical cavity surface emitting laser is reduced, the universality of material growth is improved, the free carrier absorption is reduced, and the output efficiency of the device is improved; and thevertical cavity surface emitting laser has polarization selection and single mode output characteristics, and can be expanded to a tunable vertical cavity surface emitting laser. The vertical cavity surface emitting laser can be applied to the fields such as optical communication, optical interconnection, optical sensing, medical imaging and the like.

A composite thermal barrier material. The material includes a support layer coated on one or both sides with an infrared active material to improve thermal retention characteristics. The support layer is typically a flexible organic or polymer material. The infrared active material increases reflectance of thermal infrared radiation and reduces the flow of heat from the interior side of the barrier to the external surroundings. The infrared active material operates through vibrational absorption in the infrared and/or free carrier absorption. Representative infrared active materials include oxides, transparent conductors, and nanoscale metals.

The invention provides an F-P (Fabry-Perot) cavity strained quantum well laser with low linewidth. The F-P cavity strained quantum well laser comprises a substrate (1), a buffer layer (2), an n type lower limiting layer (3), a lower waveguide layer (4), a lower barrier layer (5), an active layer (6), an upper barrier layer (7), an upper waveguide layer (8), a p type upper limiting layer (9) and an ohmic contact layer (10) which are sequentially connected. Through the optimal design of the active layer (6), a linewidth enhancement factor generated by interband transition of a quantum well and a linewidth enhancement factor generated by free carrier absorption and band-gap shrinkage can offset mutually, thereby realizing the low linewidth and improving the quality of a light beam of the quantum well laser. The active layer of the laser provided by the invention is made of InxGa1-xAs materials, wherein x is equal to 0.33, the width thickness of the well is 3-5nm, the center wavelength lambda is equal to 980nm-1036nm, and the linewidth of the F-P cavity strained quantum well laser can be reduced by three orders of magnitude in comparison with a quantum well laser. The F-P cavity strained quantum well laser can be used for optical measurement, solid-state laser pumping, laser spectroscopy research and other fields.

A photosensor for the detection of infrared radiation in the wavelength range of 1 to 1000 micrometers consists of a semiconductor substrate with a highly doped interaction volume for the incoming radiation. At the edge of this highly doped region, an extended gate electrode is placed consisting of a conducting material on top of an insulating layer. On the other side of the gate electrode, another highly doped semiconductor region is placed, acting as a charge collector. Through free carrier absorption in the interaction volume, incoming photons impart their energy on mobile charge carriers. In the case of free electrons, the gate electrode is biased slightly below the reset voltage of the interaction volume, so that the electrons carrying the additional energy of the absorbed photons can predominantly make the transition from the interaction volume across the gate electrode area to the charge collector volume.

The invention discloses a metal nanoparticle-insulator composite material grating coupler and a preparation method and an application thereof. The grating coupler is composed of a metal nanoparticle-insulator composite material coupling grating and an insulator optical planar waveguide. The metal nanoparticle-insulator composite material coupling grating is a two-dimensional orthogonal rectangular diffraction grating which is prepared on the surface of the insulator optical planar waveguide implanted with metal ions by use of electron beam lithography and reactive ion beam etching technologies based on a formed metal nanoparticle-insulator composite material modified layer. Compared with an insulator grating coupler of the same structure, the grating coupler of the invention has higher coupling efficiency, and there is no loss caused by free carrier absorption. In addition, the grating coupler is insensitive to the polarization direction of light. In the realization process of light coupling, light can be filtered, split and deflected with the aid of the formation of guided wave and diffraction distortion. The metal nanoparticle-insulator composite material grating coupler can be used in the field of preparation of large-scale integrated optical circuits.

The invention relates to an optical measurement method for resistivity of a semiconductor material. The principle of the optical measurement method is as follows: a semiconductor material generates excess carriers after absorption of a pump beam with the photon energy greater than the forbidden bandwidth; the excess carriers are subjected to radiative recombination to generate photons, and the photons are reabsorbed by the material during the process of transmitting the photons to the front and back surfaces; since the magnitude of a re-absorption coefficient is related to the photon energy, in addition to the difference in photon transmission paths, the photoluminescence spectra collected and measured by the front and back surfaces are different. The re-absorption of the photons mainly comprises intrinsic absorption and free carrier absorption; the magnitude of the free carrier absorption is related to the doping concentration of the semiconductor material, therefore, the doping concentration of the semiconductor material can be obtained by analyzing and calculating the photoluminescence spectra collected by the front and back surfaces, and the resistivity can be further calculated by a formula. According to the method of the invention, the defect that a traditional four point probe technology needs to be in contact with a sample is overcome, and the measurement precision of the resistivity of the semiconductor material is improved.

The invention belongs to the field of preparation of inorganic functional materials, and particularly relates to a medium-long-wave infrared wide-spectrum light absorption material and a preparation method thereof, the medium-long-wave infrared wide-spectrum light absorption material is formed by sequentially stacking an alumina pore structure, a silicon pore structure, a silicon nano-pore structure and a silicon substrate; and the silicon nanopore structures are distributed in the silicon hole structures and the silicon substrate. The medium-long-wave infrared wide-spectrum light absorption material is formed by stacking four layers of materials in sequence, a refractive index gradient material is formed, and high-temperature-resistant wide-spectrum light absorption of medium-far infraredbands is achieved through free carrier absorption of a silicon material with the adjustable doping concentration in the medium-long-wave infrared bands. The medium-long wave infrared wide-spectrum light absorption material is large in absorption wavelength range, high in absorption efficiency, small in absorption layer thickness, free of polarization dependence, large in incident angle range andresistant to high temperature.

The present invention is an electro-absorption modulator with a p-i-n-i-n epitaxy layer whose structure is p-i(MQW)-n⁺-i(collector)-n to release the trade-off between the operation voltage and the speed, to increase the confinement factor of the light in the un-doped layers, and to reduce the insertion loss caused by the free-carrier absorption in the doped layers, wherein MQW stands for Multiple-Quantum Well.

The invention discloses a vertical cavity surface emitting laser and a manufacturing method thereof. The laser comprises a substrate, a non-doped first Bragg reflector, a first contact layer, a non-doped lower coating layer and a non-doped first table top, and the first table top comprises an active layer and an upper coating layer which are sequentially formed on the lower coating layer; N n-type doped second table top, formed on the first table top, the second table top comprising a current expansion layer and a second contact layer which are sequentially formed on the first table top, and the side face of the second table top being subjected to p-type diffusion to form an annular diffusion region; and a non-doped second Bragg reflector formed on the second mesa. According to the invention, current limitation is carried out by using a p++ n junction depletion region through a micro-mesa side selection region p-type diffusion method, so that oxidation and multiple epitaxial processes with high difficulty and low yield are avoided. In addition, the non-doped DBR structure is adopted, so that the free carrier absorption can be reduced while the epitaxial growth difficulty is reduced.