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Gold metallization on wafer substrates for wire/ribbon bond applications requires good bond strength to the substrate without weakening the wire/ribbon. This paper compares the ribbon bondability of Cr-Au and Ti-TiN-Pt-Au metallization systems for an optoelectronic application. Both Chromium and Titanium are used to promote adhesion between semiconductor substrates and sputtered gold films. However, both will be oxidized if they diffuse to the gold surface and result in the degradation of the wire/ribbon bondability. Restoring bondability by ceric ammonium nitrate (CAN) etch was investigated. Experiments were conducted to investigate the effect of Cr-Au and Ti-TiN-Pt-Au, annealing, and CAN etch processes, on 25.4times254 mum (1 times 10 mil) ribbon bonding. All bonds were evaluated by noting pull strengths and examining specific failure modes. The results show that there is no significant difference in bondability between Cr-Au and Ti-TiN-Pt-Au before the annealing process. At this point, excellent bond strength can be achieved. However, wire/ribbon bondability of Cr-Au degraded after the wafers were annealed. The experimental results also show that a CAN etch can remove Cr oxide, and that the improvement in wire/ribbon bondability of Cr-Au depends on the CAN etch time. It is further demonstrated that the same annealing process does not have a significant effect on the bondability of Ti-TiN-Pt-Au metallization on the same type substrate materials. Auger electron spectroscopy was used to investigate the causes of the difference in bondability between these two metallizations

We present the design, fabrication, and demonstration of a 10/spl times/10 matrix-addressed vertical-cavity top-surface-emitting laser (VCSEL) array. These arrays are batch-fabricated from full 3-in diameter GaAs/AlGaAs wafers. We show that no performance-penalty is paid using top-contacted matrix addressed pixels over conventional planar VCSEL devices. A computer-controlled display system for electrically addressing the array was designed and constructed to permit video demonstration and array testing. >

Gold metallization on wafer substrates for wire/ribbon bond applications require good bond strength to the substrate without weakening the wire/ribbon. This paper compares the ribbon bondability of Cr/Au and Ti/TiN/Pt/Au metallization systems. Both chromium and titanium are used to promote adhesion between substrates and sputtered gold films. Both can diffuse the gold surface after annealing and degrade the wire/ribbon bondability. Restoring bondability by ceric ammonium nitrate (CAN) etch was investigated. Experiments were conducted to investigate the effect of Cr/Au and Ti/TiN/Pt/Au, annealing, and CAN etch processes on 25.4 times; 254 /spl mu/m (1 /spl times/ 10 mil) ribbon bonding. All bonds were evaluated by noting pull strengths and examining specific failure modes. The results show that there is no significant difference in bondability between Cr/Au and Ti/TiN/Pt/Au before the annealing process. At this point excellent bond strength can be achieved. However, wire/ribbon bondability of Cr/Au degraded after the wafers are annealed. The experimental results show that a CAN etch can remove Cr oxide. Improvement of wire/ribbon bondability of Cr/Au depends on the CAN etch time. The annealing process does not have significant effect on bondability of Ti/TiN/Pt/Au metallization. Auger electron spectroscopy was used to investigate what caused the difference in bondability between the two metallization.

Applications for lithium niobate modulators have developed in CATV, telephone and data communications markets. With deployment of devices in these systems comes the need to ensure long term reliability. In this paper we described the design, assembly, and qualification of a hermetically packaged optical modulator. The qualification devices were fabricated using a pilot production facility running at Lucent Technologies-Bell Laboratories. A variety of techniques are used to hermetically seal the Kovar package. The effects of thermal expansion mismatch between the package and the die are managed by careful package design and assembly operations. The package assembly employs a modular design which allows qualification of the subassemblies as well as the entire modulator. This design modularity allows fiber subassemblies and the lithium niobate die to be characterized for optical and mechanical performance before they are incorporated into the packaged modulator.

Magnetic bubble memories are an all solid-state, nonvolatile technology that offers a viable alternative to rotating electromechanical memory systems. Rotating memory systems such as magnetic disks, tapes, or drums are often not practical in government applications because of maintenance, reliability, and security problems. Bubble memories offer improvements in the required system reliability for these applications and lend themselves to a modular memory design not possible with mechanical systems. A 244 Mbit memory system is described which is general purpose in design, has a block random access architecture, and has demonstrated its high reliability.