Glass passivated mesa diode mfr. - by forming semiconductor layers, forming furrows, depositing sipox, glass, and nickel then dicing

摘要

Glass passivated mesa diodes are mfd. by (a) forming a semiconductor slice having a first thick layer of first conductivity type with a high level of dopant, covered with a second layer of the same conductivity type at a low-dopant level followed by a third layer of second conductivity type; (b) forming furrows in the slice according to a pattern of elementary diodes, starting from the first layer and reaching the first; (c) forming a deposition of polycrystalline silicon doped with oxygen (Sipox) on both faces of the slice; (d) depositing particles of glass in the furrows and sintering it; (e) placing the wafer in a nickel flash plating bath to form a premetallisation localised on the Sipox layer at the places where it is not coated with glass; and (f) metallising the surfaces of the wafer and cutting it into elementary diodes. The Sipox layer improves the voltage behaviour of a diode when the temp. rises. The diodes are mfd. without using masking steps, the various layers being self aligned.