Glass passivated GaAs chip tunnel diode

High-speed computers of the next generation will require ultra-fast, extremely reliable tunnel diodes at the lowest possible cost. The glass sealed, planar GaAs tunnel diode described in this paper was designed to fulfill these specified requirements. The conventional header, which is costly and delays the electrical signal, was eliminated by hermetically sealing each device with a thin glass film having a compatible thermal expansion coefficient. The single-sided planar structure together with this glass layer provides a tunnel diode which is very reliable mechanically. Thermocompression bonding was eliminated and the interconnections are made via metallic balls placed on the chips. The peak current was not tailored by the usual electrochemical process, which reduces the junction to a narrow neck structure and causes poor mechanical reliability, but tailored by employing the so-called electrical degradation phenomenon. In the actual circuit, these diodes will be biased no further than the valley, where no significant degradation has been observed. Device fabrication processes are described. Results of the investigation of peak-current tailoring by electrical current are presented, along with available device reliability data.