摘要:
A method of fabricating a semiconductor laser includes forming a mask having a stripe opening in a direction on a {100} surface of a first conductivity type substrate, and growing a double-heterojunction structure including a first conductivity type cladding layer, an active layer, and a second conductivity type cladding layer on the {100} surface using the mask, thereby producing a stripe-shaped ridge in which the active layer and the first conductivity type lower cladding layer are covered with the second conductivity type upper cladding layer. The stripe-shaped ridge has an ordinary mesa-shaped cross-section in a direction perpendicular to the stripe direction and a symmetrical hexagonal cross-section in the stripe direction. In this method, since the conventional selective etching for forming the ridge is dispensed with, the processing precision of the ridge is improved. Further, the second conductivity type cladding layer and the active layer grown on the side surfaces of the first conductivity type cladding layer are very thin and have low dopant incorporating efficiencies, so that portions of the first conductivity type cladding layer grown at the side surfaces of the ridge have high resistivity, and reactive current is blocked by these high-resistance portions.
摘要:
A material supplying apparatus includes a container for storing a solution; an inlet pipe for introducing a carrier gas and an outlet pipe; electrodes disposed in the container over the depth direction of the container and forming a capacitor; and apparatus for calculating a residual amount of the solution in the container from the capacitance of the capacitor formed by the electrodes. The solution is used as the dielectric of the capacitor formed in the container and the capacitance varies according to the quantity of solution so that the residual amount of the solution and the time to replenish the solution are calculated in a simple structure having no moving parts.
摘要:
A multi-quantum barrier layer includes alternatingly laminated barrier layers of a III-V compound semiconductor material and well layers of a III-V compound semiconductor material including the same Group V element as in the barrier layers. During the formation of the multi-quantum barrier layer it is not necessary to switch the Group V element source gas at the interface between a barrier layer and a well layer so that this interface is abrupt, improving the electron reflection efficiency of the multi-quantum barrier layer.
摘要:
A multiquantum barrier (MQB) structure includes a first superlattice layer and a second superlattice layer disposed continuously with the first superlattice layer. The first superlattice layer includes well layers having the same thickness and barrier layers having the same thickness, the well layers and barrier layers being alternatingly laminated. The second superlattice layer includes well layers having the same thickness, the well and barrier layers being alternatingly laminated. The second superlattice layer has a high electron reflectivity in an electron energy region where the electron reflectivity of the second first superlattice structure is low. Therefore, the high reflectivity of the second superlattice layer compensates for the low reflectivity of the first superlattice layer whereby a high electron reflectivity is maintained in the MQB structure.
摘要:
A method of fabricating a semiconductor laser producing visible light includes forming a double heterojunction (DH) structure on a GaAs substrate including an n type GaAs buffer layer, an n type AlGaInP cladding layer, an Al.sub.x Ga.sub.(1-x) InP active layer, a first p type AlGaInP cladding layer, a p type GaInP etch stopping layer, a second p type AlGaInP cladding layer, and a p type GaAs cap layer. A stripe-shaped mask is formed on the DH structure, the p type GaAs cap layer is selectively etched using the mask, and the second p type AlGaInP cladding layer is selectively etched to the p type GaInP etch stopping layer to form a stripe-shaped ridge. Therefore, a high precision ridge can be formed easily.
摘要翻译:制造可见光的半导体激光器的方法包括在包括n型GaAs缓冲层,n型AlGaInP包层,Al x Ga(1-x)InP活性层, 第一p型AlGaInP包覆层,p型GaInP蚀刻停止层,第二p型AlGaInP包覆层和ap型GaAs覆盖层。 在DH结构上形成条状掩模,使用掩模选择性地蚀刻p型GaAs覆盖层,并且将第二p型AlGaInP包层选择性蚀刻到p型GaInP蚀刻停止层以形成条形 岭。 因此,可以容易地形成高精度的脊。
摘要:
A method of etching a III-V compound semiconductor uses an etching gas including the group V element of the III-V compound semiconductor substrate layer while keeping the III-V compound semiconductor layer at a temperature higher than the crystal growth temperature of the III-V compound semiconductor. Etching using this method provides a higher degree of controllability than wet etching. In addition, because no etching solution is employed, the etching method can be employed in a crystal growth apparatus. Further, because an element of the III-V compound semiconductor layer is employed in the etching gas, incorporation of residual impurities can be prevented, keeping the etched surface clean.
摘要:
An apparatus for zone-melting recrystallization of a semiconductor layer includes a first heater, on which a semiconductor wafer including the semiconductor layer and upper and lower insulating films sandwiching the semiconductor layer is mounted, for radiantly heating a rear surface of the semiconductor wafer to a temperature at which the semiconductor layer and the insulating layers are not melted; and a second heater disposed above the semiconductor wafer and radiantly heating a front surface of the semiconductor wafer. The second heater has a heat generating point that produces a heated spot in the semiconductor layer and moves spirally while maintaining a fixed distance from the semiconductor wafer, thereby producing a large-area monocrystalline region in the semiconductor layer. In this zone-melting recrystallization, a single crystalline nucleus is produced in the semiconductor layer, and the entire semiconductor layer is recrystallized with the crystalline nucleus as a seed crystal. Therefore, the semiconductor layer is recrystallized with the same crystal structure and orientation as the crystalline nucleus, so that grain boundaries are reduced, resulting in a semiconductor layer with increased grain size.
摘要:
A method of fabricating a semiconductor laser includes forming a mask having a stripe opening in a direction on a {100} surface of a first conductivity type substrate, and growing a double-heterojunction structure including a first conductivity type cladding layer, an active layer, and a second conductivity type cladding layer on the {100} surface using the mask, thereby producing a stripe-shaped ridge in which the active layer and the first conductivity type lower cladding layer are covered with the second conductivity type upper cladding layer. The stripe-shaped ridge has an ordinary mesa-shaped cross-section in a direction perpendicular to the stripe direction and a symmetrical hexagonal cross-section in the stripe direction. In this method, since the conventional selective etching for forming the ridge is dispensed with, the processing precision of the ridge is improved. Further, the second conductivity type cladding layer and the active layer grown on the side surfaces of the first conductivity type cladding layer are very thin and have low dopant incorporating efficiencies, so that portions of the first conductivity type cladding layer grown at the side surfaces of the ridge have high resistivity, and reactive current is blocked by these high-resistance portions.
摘要:
A method of fabricating a semiconductor laser includes forming an active layer including a compound semiconductor material on a semiconductor substrate, the compound semiconductor material having an energy band gap that monotonically increases as the growth temperature of the material rises above a certain growth temperature, including growing a window structure forming region including at least a region which serves as a waveguide in the proximity of a laser resonator facet at a higher temperature than a region outside the window structure forming region. Therefore, the band gap energy of the window structure forming region is larger than that of the region outside the window structure forming region. Therefore, a semiconductor laser having a window structure can easily be fabricated with a high yield and with great repeatability.
摘要:
A fuel cell system having a fuel cell includes a power generation-time gas supplier that supplies hydrogen-containing fuel gas to an anode of the fuel cell and supplies an oxygen-containing oxidizing gas to a cathode of the fuel cell during power generation of the fuel cell. The fuel cell system also includes an anode potential rise information acquirer that acquires anode potential rise information, which represents information regarding a status of an anode potential rise of the fuel cell, after termination of supplies of the fuel gas and the oxidizing gas by the power generation-time gas supplier. The fuel cell system further includes an anode morphology variation deriver that derives an anode morphology variation representing a degree of a morphology change of a catalyst metal included in the anode, based on the anode potential rise information.