SVG guard-ring Al-Ti-Si schottky diode for high-speed LSI applications

The SVG (shallow V-groove) guardring fabrication technique for Schottky diodes allows a high packing density, a high breakdown voltage, a low leakage and a small junction capacitance to be achieved. By evaporation of a thin titanium film under an aluminum film, the barrier heights of the contacts can be shifted slightly from that of a Al-Si Schottky diode toward thatof a Ti-Si Schottky diode. The barrier height of 0.61 eV was determined by the JF/VF and JF/T2/1/T characteristics. The breakdown voltages of 240 randomly chosen devices were measured at a reverse current level of 1 ¿A. The high typical breakdown voltage of 26.5 V and its narrow distribution indicate that the field peaking along the periphery of the metal contacts was eliminated by the SVG guard ring. The SVG guard ring blocks the lateral spread of the depletion layer and reduces the junction capacitance to 70% of that of a Schottky diode without guard ring.