Abstract: Disclosed is a technique useful in the manufacture of semiconductor devices. When a semiconductor device is manufactured by the temperature gradient zone melting process, it is subjected to a short diffusion cycle following thermomigration. The cycle smooths out discontinuities caused by breaks in wire migration and effectively seals and isolates occluded particles of the impurity remaining in the semiconductor body. The cycle is also useful for providing large area doped regions that cannot be formed by wire migration due to constraints on wire direction.

Abstract: Disclosed is an isolated semiconductor assembly with a pellet mounting plate having a beveled periphery and surmounted by a semiconductor pellet. A ribbon-shaped lead overhangs the edge of the top of the pellet and terminates in the plane of the lower side of the mounting plate. A ceramic substrate has conductive leads bonded thereto, portions of which are in registry with and bonded to the plate and ribbon-shaped lead. External connections can be made to other areas of the conductive leads.

Abstract: Disclosed is a method for selectively doping semiconductor materials utilizing temperature gradient zone melting. The required temperature gradient is provided by infrared radiation impinging on and heating one surface of a body of semiconductor material to be doped. The heat is conducted through the body creating a temperature gradient.

Abstract: Disclosed is a breakage resistant semiconductor wafer and a method for the fabrication thereof. Intersecting grooves are formed on one side of the wafer to facilitate ultimate subdivision thereof. A portion, such as a peripheral portion, of the wafer remains ungrooved. The ungrooved portion substantially increases the strength of the wafer and prevents premature breakage. When it is desired to subdivide the wafer, laser scribe lines are formed on the opposite side of the wafer in registry with the grooves. In an alternate embodiment the second side of the wafer is also grooved. However, the grooves on the second side of the wafer traverse the entirety thereof.

Abstract: Disclosed is an assembly with a semiconductor pellet mounting plate that defines two substantially parallel major surfaces, at least one surface having a central planar region surrounded by a smaller peripheral transition region such that the periphery of the major surface is recessed and out of the plane of the central planar region. A semiconductor pellet is mounted on the central planar region and the metallic contacts on the pellet are substantially coextensive with the central planar region. The peripheral transition region can take any of several disclosed forms.

Abstract: Disclosed is a method of bonding metals to substrates such as ceramics or metals. A bonding agent forms a eutectic alloy with the metal to provide bonding. Several methods of supplying the bonding agent to the system are disclosed. However, regardless of which method of introducing the bonding agent into the system is employed, the quantity of the bonding agent is carefully controlled so that the compound in the region of the bond is hypoeutectic. To form the bond, the metal and the substrate are placed adjacent each other and the bonding agent is introduced into the system. The system is then heated to a temperature between the eutectic temperature and the melting point of the metal for a preselected time. The system is then cooled to form a bond. The heating is carried out in an inert atmosphere or a vacuum.

Abstract: A semiconductor device in which a top-contact semiconductor body is thermo-electrostatically face down bonded to a vitreous support carrying patterned metallization forming leads registered with the top contacts, and a protective insulative coating is provided over at least portions of the leads to preclude shortcircuiting to exposed portions of the semiconductor body.

Abstract: Disclosed is an etchant for removing a metal, such as titanium, from a glass substrate without adversely attacking the glass. The etchant includes a relatively viscous coating agent that wets and coats and thus protects the glass but does not wet the metal thus permitting etching thereof. A nonionizing diluent can be included in the etchant to inhibit the etching rate if it is felt that the heat and turbulence that would otherwise be generated may be excessive and interfere with the action of the coating agent.

Abstract: Disclosed is a method for selectively etching portions of the surface of a semiconductor body. Selected regions of the surface which are not to be etched are covered with a pliable membrane such as a plastic sheet that conforms to the shape of the body and forms a seal with the body. The combination of the membrane and body is then exposed to an etchant which only contacts the exposed portions of the body. Conformity of the membrane can be enhanced by any of several methods.For example, heat can be applied to make the membrane more pliable, a vacuum can be drawn between the membrane and the body or mechanical pressure can be applied to urge the membrane against the body. The aforementioned conformity enhancement steps are used during the covering operation, either individually or in combination.

Abstract: Disclosed is a metal oxide varistor consisting primarily of metal oxide with a small percentage of preselected additives distributed substantially evenly therethrough. A grain growth inhibitor is combined with the metal oxide powder forming a final mix with peripheral regions having a high concentration of the inhibitor that surround and separate interior regions that have a low concentration of the inhibitor. Varistor bodies are formed from the final mix and the peripheral and interior regions retain their identities in the varistor bodies. The bodies can be pressed and sintered in the conventional manner. During sintering the grains within each interior region tend to combine and grow. However, growth is stopped at the peripheral regions due to the high concentration of inhibitor. Thus, the grain size in the processed pellet is dependent upon the size of the interior regions which can be controlled.

Abstract: By protecting one surface of a silicon element with an oxide layer while leaving another surface exposed it is possible to diffuse both gallium and phosphorus into the silicon element simultaneously in a selective manner. Gallium will penetrate the oxide layer while phosphorus will not, thereby forming a P conductivity type layer beneath the oxide layer. At the same time both gallium and phosphorus will diffuse into the remaining surfaces of the element. A higher concentration of phosphorus than gallium will diffuse to all depths, thereby forming an N conductivity type layer adjacent the exposed surface of the silicon element.

Abstract: Disclosed is a bidirectional triode thyristor pellet that comprises two current conductive regions and a gate region. Gold is diffused into the boundaries between the several regions to inhibit carrier migration thereacross and thus reduce turnoff time. Also disclosed is a method of fabricating the subject thyristor pellet that permits glass passivation thereof if desired.

Abstract: Disclosed is a method for fabricating semiconductor devices and apparatus that can be used in the practice thereof. A plurality of sets of lead wires is mounted in a reusable primary lead frame. While supporting the lead frame, and thus the lead wires, a pellet is attached to one wire of each of the sets and appropriate flying leads are bonded in place. The sets of lead wires are then transferred to a reusable segmented lead frame, that includes a plurality of elements which are resiliently mounted with respect to each other. Each element supports one set of lead wires. A plurality of cup-shaped mold cavities defined by the mold are filled with a curable fluid encapsulant. The mold is adapted to cooperate with the segmented lead frame as hereinafter set forth. The ends of the lead wires supporting the pellets are immersed in the encapsulant.

Abstract: A metal oxide varistor comprising a body portion that is composed essentially of a metal oxide and a small percentage of a plurality of preselected additives. A passivating coating is applied to the body portion prior to the application of metallic contacts. The passivating coating includes at least some of the preselected additives in order to enhance device stability and insure compatibility therewith.