Abstract: Herein provided is an electrostatic chuck whose surface is processed so as to have projections and recesses, which has a simple structure and which makes it possible to establish a uniform temperature distribution on a wafer surface when the wafer is held on the processed surface thereof through the use of an electrostatic attractive force. The uneven surface configuration of the electrostatic chuck is designed so that the proportion of the area occupied by the projected surface in the peripheral portion, i.e., in the relatively outer region of the surface, is smaller than that of the area occupied by the projected surface in the central portion, i.e., in the relatively inner region of the surface of the electrostatic chuck, in order to change the rate of heat transmission so as to be larger in the central portion than in the peripheral portion between the wafer and the electrostatic chuck. In this case, the height of the projections is limited to the range of from 10 to 70 .mu.

Abstract: A method for producing a semiconductor laser of InGaAsP/InP type having a structure, in which an active layer isolated from outside is embedded in a groove in a substrate wafer, which comprises steps of: forming the groove in the substrate having a crystallographic plane of (100), on the upper surface of which a current blocking layer has been formed, along the <011> direction of the substrate, in a manner to be terminated at both sides of substrate wafer in the vicinity of the end faces of a laser resonator; and, thereafter, sequentially forming on the groove and other regions of the substrate clad layers and the active layer.

Abstract: A method of fabricating a semiconductor laser stably operable at high temperatures over long periods of time and with a low leakage current. A semiconductor wafer is prepared including a semiconductor substrate of a first conductivity type and a current blocking layer formed thereon, the current blocking layer including at least one semiconductor layer of a second conductivity type. A groove is formed in the upper surface of the wafer having a depth corresponding to at least the thickness of the current blocking layer. At least surface regions of the wafer are removed in the vicinity of the groove and upper sidewall surface regions of the groove using a semiconductor solution. A plurality of semiconductor crystal layers are then grown on the wafer, including a layer consistuting an active region in the groove, by liquid phase epitaxy.

Abstract: A semiconductor laser device in which the thickness and position of an active layer grown in a groove are made more controllable. The inventive device includes a buffer layer of a first conductivity type formed on a semiconductor substrate of the same conductivity type, a first current blocking layer of a second conductivity type formed over the first buffer layer, the aforementioned groove being formed through the first and current blocking layer to the buffer layer, the active layer buried in the groove, and mesas formed on both side of the groove. With this structure, during crystal growth of the active layer, atoms which would otherwise diffuse into the groove and make it difficult to control the thickness and position of the active layer diffuse into portions outside the mesas and grow thereon.

Abstract: In order to prevent the output characteristic of a semiconductor laser from being saturated at higher temperatures due to the thyristor effect of a combination of the semiconductor layers thereof, an intermediate layer of a conductivity type the same as that of the substrate and opposite that of the first semiconductor layer is provided between the substrate and the first layer. Due to the relatively low carrier density of the intermediate layer, oscillation can be stably carried out even at higher temperatures without triggering the thyristor structure.