At&t Bell Laboratories

Other

Lucent Technologies Inc.

Avishay Katz

King Lien Tai

William C Dautremont-Smith

Chien-Hsun Lee

Louis A Koszi

Yiu-Man Wong

Bryan P Segner

Peter M Thomas

Sungho Jin

Barry Irwin Miller

Leonard C Feldman

Michael Geva

Ho S Chen

John E Graebner

Cheng-Hsuan Chen

Rafael Kalish

Donald D Bacon

Donlad D Bacon

David I Caplan

Netzer Moriya

A method for bonding one body to another, such as a laser device to a submount, uses a metallic layer composed of a Group VB metal, such as niobium, sandwiched between a non-metallic layer and solder layer formed by an approximate Au-Sn eutectic layer. Advantageously the Group VB layer is formed at a submount temperature of less than approximately 201.degree. C., advantageously less than approximately 125.degree. C., and preferably less than approximately 101.degree. C.--advantageously to a thickness in the approximate range 0.05 .mu.m to 0.2 .mu.m, or even thinner if pinholes do not develop. The non-metallic layer is located on one of the bodies, and the other body has a metallic coating advantageously capped with an Au layer.

Bonding scheme using group VB metallic layer

A diamond body, such as a CVD diamond film, is etched by immersion of the body in a molten or partially molten metal, such as the rare earth metal La or Ce. While the body is being etched, various portions of a major surface of the body can be protected for various time durations by masks against the etching--whereby, after dicing the body, the resulting dies can be used as submounts for lasers with feedback.

Etching a diamond body with a molten or partially molten metal

A graphite path is formed along the surface of a diamond plate, preferably a CVD diamond plate, by means of a laser or ion-implantation induced conductivity. The path advantageously can be the surface of a sidewall of a via hole drilled by the laser through the plate or a path running along a side surface of the plate from top to bottom opposed major surfaces of the plate. The graphite path is metallized, as by electroplating or electroless plating. In this way, for example, an electrically conducting connection can be made between a metallized backplane located on the bottom surface of the plate and a wire-bonding pad located on the top surface of the plate.

Metallized paths on diamond surfaces

One or more metallized chip terminals of an electronic device, such as an integrated circuit chip or a laser chip, in one embodiment are temporarily bonded to one or more metallized substrate pads of a wiring substrate, as for the purpose of electrically testing the electronic device. The composition of the metallized chip terminals is suitably different from that of the metallized substrate pads. The pads and terminals are aligned and electrically connected together with a solder located between them under pressure and a temperature above the melting point of the solder. The solder is cooled, and electrical tests of the electronic device are performed by means of electrical access from testing circuitry to the chip terminals through the substrate pads. Then the solder is heated again above its melting point while being immersed in a liquid flux, whereby the liquid solder wets the metallized chip terminals but not the metallized substrate pads, and the device is gently mechanically pulled away from the wiring substrate and is cooled thereafter. This substrate can thereafter be reused for testing other electronic devices that have similarly suitably metallized terminals. In another embodiment, testing can be performed or not as may be desired; and, as for the purpose of chip operation as an integrated circuit or laser, the chip can be allowed to remain permanently bonded to the substrate in the form of a heat-sinking or heat-spreading submount, or it can be allowed to remain only temporarily bonded to the submount and subsequently pulled away from the submount for the purpose of reuse of the submount for another chip.

Debondable metallic bonding method

A laser device is bonded to a diamond submount by means of a procedure including (1) codepositing an auxiliary layer, on a layer of barrier metal that has been deposited overlying the submount, followed by (2) depositing a wetting layer on the auxiliary layer, and (3) by depositing a solder layer comprising alternating metallic layers, preferably of gold and tin sufficient to form an overall tin-rich gold-tin eutectic composition. The barrier metal is typically W, Mo, Cr, or Ru. Prior to bonding, a conventional metallization such as Ti-Pt-Au (three layers) is deposited on the laser device's bottom ohmic contact, typically comprising Ge. Then, during bonding, the solder layer is brought into physical contact with the laser device's metallization under enough heat and pressure, followed by cooling, to form a permanent joint between them. The thickness of the solder layer is advantageously less than approximately 5 .mu.m. The wetting layer is preferably the intermetallic compound Ni.sub.3 Sn.sub.4, and the auxiliary layer is formed by codepositing the metallic components of this intermetallic together with the barrier metal.

Permanent metallic bonding method

A semiconductor device substrate has a major surface on which is located an insulating layer, such as silicon dioxide, having an aperture penetrating through it all the way down to the major surface. An impurity-doped plug, such as tungsten doped with zinc, is spatially selectively deposited in the aperture to a thickness such that the height of the plug is significantly less than the height of the aperture in the insulating layer, by means of a rapid-thermal-cycle low-pressure-metalorganic-chemical vapor deposition (RTC-LP-MOCVD) process. Then another plug, of (pure) conductive barrier metal such as tungsten, is deposited on at least the entire top surface of the impurity-doped plug and on the sidewalls of the insulating layer. The structure being fabricated can then be heated, in order to diffuse the impurity into the underlying semiconductor device substrate. A metallization layer such as titanium/platinum/gold can be deposited on the (pure) conductive barrier metal and patterned, in order to supply a desired access metallization for the device.

Method of fabricating contacts for semiconductor devices

A laser assembly including a diamond film submount is formed by anisotropically etching a localized indentation (recess) region in an originally completely planar face of the film. The region has one or pair of intersecting sidewalls preferably making the same angle between them as an angle made between a pair of sides of a laser device. After metallizing the remaining top face of the film, the bottom of the indentation region, and one or both of the sidewalls of the indentation region, the laser device is pushed into position in the recess with its above-mentioned pair of sides lying against one of the sidewalls and the metallization of the other sidewall, or lying against the metallization of both sidewalls; and the bottom of the laser device is quickly bonded by means of solder to the metallization on the bottom of the recess. Also, the metallization of the top face of the film is patterned using as a protective patterned mask a patterned electrically conducting layer having a prescribed resistivity, so that after further patterning it can serve as a resistor during normal electrical operation of the laser device.

Assembly including patterned diamond film submount with self-aligned

A device such as a laser is bonded to a submount such as diamond by a process in which the submount is successively coated with an adhesion layer such as titanium, a barrier layer such as nickel, and a gold-tin solder-metallization composite layer formed by sequential deposition on the barrier layer a number (preferably greater than seven) of multiple alternating layers of gold and tin, the last layer being gold having a thickness that is equal to approximately one-half or less than the thickness of the (next-to-last) tin layer that it contacts immediately beneath it. The bonding is performed under applied heat that is sufficient to melt the solder-metallization composite layer. Prior to the bonding, (in addition to the submount) the device advantageously is coated with gold and optionally with a similar gold-tin solder-metallization composite layer, at least at locations where it comes in contact with the gold-tin solder-metallization composite layer.

Bonding method using solder composed of multiple alternating gold and

Disclosed is a method of making a semiconductor device that exemplarily comprises depositing a Ti/Pt layer onto a AuBe intermediate layer on a p-doped region of a semiconductor body. It also comprises depositing a Ti/Pt layer onto a n-doped region of the semiconductor body, or onto a AuGe intermediate layer on the n-doped region, followed by rapid thermal processing. Exemplarily, the device is a semiconductor laser, the n-doped region is InP, the p-doped region is InGaAs or InGaAsP, and RTP involves heating in the range 425.degree.-500.degree. C. for 10-100 seconds. The method comprises fewer processing steps than typical prior art methods, reduces the danger of fabrication error and of wafer breakage and, significantly, results in contacts that can be relatively thermally stable and can have very low specific contact resistance (exemplarily as low as 10.sup.-7 .OMEGA..multidot.cm.sup.2).

Method of making a semiconductor device

Disclosed is a method that comprises selective deposition of titanium nitride TiN.sub.x on III-V compound semiconductor material. The TiN.sub.x can advantageously be used as contact metal. Exemplarily, deposition is by rapid thermal low pressure (RT-LP) MOCVD using dimethylamidotitanium with H.sub.2 carrier gas.

Method of making an article comprising a TiN.sub.x layer

The inventive method of producing a device having non-alloyed ohmic contacts of common composition to both an n-doped and a p-doped region of a semiconductor body comprises deposition of a Ti/Pt layer on the p-doped as well as the n-doped region, followed by rapid thermal processing (RTP). Exemplarily, the device is a semiconductor laser, the n-doped region is InP, the p-doped region is InGaAs or InGaAsP, and RTP involves heating in the range 425.degree.-475.degree. C. for 10-100 seconds. The method comprises fewer processing steps than typical prior art methods, reduces the danger of fabrication error and of wafer breakage and, significantly, results in contacts that can be relatively thermally stable and can have very low specific contact resistance (exemplarily as low as 10.sup.-7 .OMEGA..multidot.cm.sup.2).

Growing community of inventors

Westfield, NJ, United States of America

Avishay Katz