Abstract: In a method of manufacturing an ink-jet printer which uses a thin film sheet having adhesive layers respectively formed on the top and bottom sides, as an orifice plate, orifices are formed in the ink-ejecting side of the thin film sheet after the adhesive layer on that ink-ejecting side has been removed. This prevents the formation of the orifices from being adversely affected by any otherwise residual of the adhesive layer and can thus permit accurate formation of orifices of a desired shape. Even if helicon-wave dry etching which ensure fast etching using high-power energy is used to form orifices, therefore, no adhesive layer is thermally expanded to be a residual so that multiple orifices can be formed simultaneously and quickly.

Abstract: According to a first aspect of the invention, a light-emitting and light-sensing diode has a doped region with a depth not exceeding 2 .mu.m, for adequate sensitivity, and an impurity concentration of at least 5.times.10.sup.20 atoms/cm.sup.-3, for adequate emission. According to a second aspect of the invention, a light-emitting and light-sensing diode has a doped region with a deep part and a shallow part, and the area of the shallow part is increased to enhance the sensitivity of the diode. This may be done by providing the doped region with a meandering edge, or with one or more interior islands, or by forming the deep and shallow parts separately.

Abstract: A semiconductor device and a method of manufacturing the same are disclosed. The device comprises a GaAs semiconductor body, a source and a drain region formed in the semiconductor body, a channel region placed between the source and drain regions, a source and a drain electrodes provided by patterning treatment onto the surfaces of the source and drain regions and making ohmic contact thereto, and a gate electrode provided onto the surface of the channel region and consisting of a W-Al alloy.

Abstract: The high frequency semiconductor device of the present comprises a pair of diodes and a transfer switch. The anode electrodes of the diodes are connected together and the transfer switch operates to connect the cathode electrode of one diode to ground and the cathode electrode of the other diode to a voltage source so as to forwardly bias one diode and reversely bias the other diode. By the selective operation of the transfer switch, the device operates either as a switch for passing high frequency signals or as an attenuator for high frequency signals.