Abstract: An improved method of mounting electroluminescent semiconductor laser devices onto heatsinks, wherein easy subsequent location of the lasing spot of the laser is provided, is disclosed. The method comprises placing a reference mark on the front of the heatsink, wetting solder to the heatsink and allowing it to harden, contacting the laser device to the hardened solder, applying current to the laser device to cause light emission, aligning the lasing spot to the reference mark and bonding the laser device to the heatsink while maintaining such alignment.

Abstract: A low coherence light-emitting device comprises a semiconductor body with a pair of end faces, The device contains an optical beam path which has an axis of symmetry extending between the end faces. At least one of the end faces is inclined at an angle which is nonperpendicular to the optical axis and the tangent of this angle is greater than or equal to the width of the beam path divided by the length of the body between the end faces. The device may be made by forming at least one of the end faces such that the end face is inclined at an angle relative to a plane perpendicular to the optical axis. The tangent of the angle is greater than or equal to the width of the optical path divided by the length of the body between the end faces.

Abstract: A device header with a multilayer coating overlying its entire surface, and a method of making said header, are disclosed. The multilayer coating comprises an electrolytic nickel layer and a gold layer in the device mounting area of the header, whereas the rest of the header is coated with electroless nickel, a first gold layer, electrolytic nickel, and a second gold layer. In the fabrication, the electroless nickel layer is deposited over the entire header followed by the first gold layer. Upon removing these layers from the device mounting area, the first gold layer remaining on the rest of the header acts as a mask for the etching of the mounting area preparatory to deposition of electrolytic nickel and the second gold layer. The header has the advantage of the excellent coverage of electroless nickel over most of its surface, but with the advantage of high purity electrolytic nickel in the device mounting area.

Abstract: An apparatus and method for imparting a sharp, defect-free outside corner of a desired angle to a metal workpiece are disclosed. The apparatus comprises two separate cutting tools, each with a distinct cutting direction. The tools are juxtaposed such that their leading surfaces are adjacent to each other and that their respective cutting edges intersect at the desired angle. This provides that the cutting directions of each tool are opposite one another. In using the improved cutting apparatus, the workpiece is secured and the apparatus must be movable along the x, y and z axes. By cutting the first and second surfaces of the workpiece in sequence with the first and second cutting edges of the present apparatus respectively, a sharp defect-free corner of the desired angle can be imparted to the workpiece. A specific application for the present invention is in the fabrication of intricate copper products, such as heatsinks for semiconductor devices.

Abstract: A die bonder for bonding a semiconductor die to a substrate is disclosed. The die bonder comprises a support assembly within a frame, which assembly supports an arm. Attached to said arm is a means for holding a die, e.g. a vacuum collet. A variable electrical scrubbing means comprises a plunger which oscillates reciprocally within an electromagnetic coil and contacts the arm, or a tab integral with said arm. This provides a corresponding uniform scrubbing action, perpendicular to said arm in the plane of the interface between the die and the substrate, between a die held by the holding means and a solder material interposed between the die and substrate.

Abstract: An improved method of selectively depositing coatings onto bodies of semiconductor material employs as a protective mask an alkyl ester of a sulfosuccinate salt. The mask material is applied to areas which are to be kept free of the coatings. The overspray of a desired coating, onto the protective mask is deposited in a cracked, non-continuous manner, as opposed to the smooth crystalline layer being deposited over the semiconductor body. This overspray coating can be readily removed.

Abstract: An improved burnishing method suitable for planarizing bonding pads on fragile semiconductor devices is disclosed. The method comprises imparting scratches of predetermined depth and spacing onto a glass slide. The bonding pad surface is contacted to the scratched glass surface under a desired pressure and a relative motion is established therebetween. The motion is continued until a smooth, defect-free bonding pad surface has been provided.

Abstract: A method for matching the bonding pad surfaces of a device and heatsinks to be bonded, which method maximizes the uniformity of pressure applied during thermocompression bonding, is disclosed. The method comprises using the collet of a die bonding machine to burnish the bonding pad on a heatsink. The collet is then traversed to a second workstage where the collet is used to pick up a device and burnish the device bonding pad against a suitable burnishing medium. The collet, with the device, is then traversed back to the main workstage where thermocompression bonding of the device to the heatsink is carried out. The alignment of the collet is locked and maintained throughout all of the steps to insure that all burnished surfaces are parallel and that the pressure during bonding is perfectly perpendicular to those parallel surfaces.

Abstract: A method for liquid phase epitaxy maskless deposition of a III-V compound on a substrate in a pre-determined pattern includes the steps of contacting a growth wafer having a patterned mask thereon to a growth solution in equilibrium and then increasing the temperature of the growth solution and wafer thereby locally melting the exposed portions of the wafer surface and locally changing the equilibrium properties of the growth solution. The substrate upon which the material is to be deposited is then contacted with the growth solution and the temperature lowered. Because of the locally varying equilibrium conditions the constituents of the growth solution will be preferentially deposited on those portions of the substrate corresponding to the unmasked portions of the growth wafer.

Abstract: In order to prevent the formation of indium droplets upon the surface of an indium phosphide wafer during liquid phase epitaxial growth, a doped protective layer is deposited by LPE upon said substrate before epitaxial growth of additional layers occurs. The doped protective layer is composed of indium phosphide doped with tellurium to a concentration of about high 10.sup.18 to low 10.sup.19.

Abstract: A method of bonding photodetector devices to heatsinks, which devices can be damaged above 250.degree. C., using a gold-tin eutectic solder which has a melting point of 280.degree. C., is disclosed. The process comprises heating the heatsink and solder past the solder melting point on a quick thermal response heating element, turning off the heating power, and introducing the chip into the liquid solder on the cool down cycle. By controlling the rate at which the heatsink solder and device cool down and the time span from introduction of the chip to solidification of the solder, the chip can be exposed to sufficient heat to provide a good thermal, electrical and physical bond while substantially enhancing the yield of electrically undamaged photodetector chips.

Abstract: An indium phosphide semiconductor layer or layers are simultaneously doped with groups II-VI elements such as zinc and selenium. These simultaneously (acceptor/donor) doped layers offer improved characteristics when used as an ohmic contact capping layer of indium phosphide or as the active laser region in long wavelength light emitting diodes composed of indium phosphide. The simultaneous doping is achieved through the use of liquid phase epitaxy.

Abstract: An improved process for electroplating bonding pads, such as of gold, onto semiconductor devices is disclosed. Upon electrically connecting a masked semiconductor body and a suitable anode to the negative and positive terminals respectively of a power supply and submerging the wafer and anode into a suitable electrolyte, a modulated, rather than direct, current is applied to the electrolyte. A low stress, fine grain bonding pad layer is provided and, unexpectedly, non-planarities in the semiconductor body surface having a depth of about 1-3 microns can be substantially planarized when the thickness of the layer deposited is about 6-8 microns or more.

Abstract: The invention is a method of soldering a light emitting device to a substrate which uses a vee-groove to hold the substrate, solder and light emitting device in accurate alignment to one another during the melting and solidification of the solder.

Abstract: A multiple double heterojunction buried laser device is formed of a bulk structure, a plurality of double heterojunction buried lasers and electrical means. The bulk structure includes, in order, an InP:Sn substrate, an InP:Te first layer, an InP:Zn second layer, an InP:Te third layer, and a capping n-type fourth layer. Multiple stripe-like openings are formed in the above layers and double heterojunction buried lasers are formed therein. The double heterojunction buried lasers include the following layers in order: an InP:Te heterojunction first layer, an InGaAsP quarternary second layer, an InP:Zn heterojunction third layer, and an InGaAsP:Zn capping fourth layer. A reverse biased junction is formed in said bulk structure so that current is confined to the lasers; the active lasing regions are above the p-type layers of the p-n reversed bias junction. The double heterojunction buried lasers can be cleaved from the laser device and operated as a single device.

Abstract: A diffusion barrier is created in a n-type heterojunction layer adjacent to the active region of a semiconductor laser by doping the n-type layer with a periodic table group VI element. The diffusion barrier in the n-type layer prevents the migration of acceptors into that layer. The group VI elements are, in particular, sulfur (S), selinium (Se), and tellurium (Te). The acceptor of concern is zinc (Zn).

Abstract: A wide band gap semiconductor alloy having a combination of P, In, Te, and Zn is formed by liquid phase epitaxy on an InP substrate. This alloy can be used for the formation of p-n junctions.

Abstract: The invention is an improved light emitting device comprising a light emitting element mounted on a header wherein the improvement comprises a thin layer of copper overlying the surface of the header including both the base and the stud. A large increase in the yield of useable devices is obtained for a light emitting element mounted on the header which emits between about 1.0 and about 1.7 micrometers.

Abstract: A semiconductor laser diode includes a substrate of indium phosphide of one conductivity type having on a surface thereof an indium phosphide first confinement layer of the same conductivity type followed by an active layer of indium gallium arsenide phosphide and an indium phosphide second confinement layer of the opposite conductivity type. On the second confinement layer is an indium gallium arsenide phosphide capping layer of either conductivity type having a stripe shaped opening therethrough. In the opening in the capping layer is a contact layer of indium gallium arsenide phosphide of the opposite conductivity type. The confinement layers, the active layer and the capping layer are formed by liquid phase epitaxy and the contact layer is formed by vapor phase epitaxy.

Abstract: In making a laser diode by a method which includes epitaxially depositing a plurality of layers of a semiconductor material on a substrate, the final outermost layer deposited is of a material which has a band-gap lower than the preceding adjacent layer, which readily accepts a conductivity modifier, which can be selectively etched from the preceding adjacent layer and which preferably has a lattice parameter substantially equal to that of the preceding adjacent layer. A conductivity modifier is then diffused along a narrow stripe into and through the outermost layer, into the preceding adjacent layer. The outermost layer is then etched away to expose the surface of the preceding adjacent layer and a metal contact is applied to the exposed surface.