Trench Isolation Schemes for Bipolar Devices --- Benefits and Limiting Aspects

This paper gives a review of benefits and limiting aspects in trench isolation techniques for bipolar deviices. The most sophisticated trench isolation techniques have realized not only higher packing densities but reduced collector-substrate, wiring-substrate and base-collector parasitic capacitances. By using these techniques, high performance bipolar devices have been fabricated while crystal defects caused by trench structures are the serious problem. Trench isolaltion techniques are still in progress, and it seems now that there is no apparent limiting aspect until the trench width reaches the filler material width to sustain enough breakdown voltage.