Planar semiconductor structure breakdown voltage protection using voltage divider

Claim 1

A planar semiconductor structure having a monocrystalline semiconductor chip (10) of a basic material having a specific conductivity type and having a main surface, a first zone (11), of the opposite conductivity type, introduced by diffusion into the first semiconductor chip (10) from one main surface, which first zone, together with the basic material making up the semiconductor chip (10), prior to said diffusion, forms a first p-n junction (12) having a line of intersection with said main surface, a second, annular zone (14), of the same conductivity type as the basic material making up the semiconductor chip (10) but having a higher concentration of impurities, introduced around the first zone (11) by diffusion into the semiconductor chip (10) from said main surface, a passivation layer (13) covering said main surface of the semiconductor chip (10) except for contact windows (301, 302, 303) disposed respectively on each of said first (11) and second (14) zones, a metallizing coating (15), annularly surrounding the first p-n junction (12) and overlapping the line of intersection thereof with said one main surface of the semiconductor chip (10), applied, acting as a cover electrode (15), to the passivation layer (13), the metallizing coating extending across said one main surface as far as a region of said one main surface adjacent to the annular zone (14), and wherein, in accordance with the invention, the second annular zone (14) acts as a stop-ring and is completely covered by the passivation layer (13), a voltage divider (16) is provided, for adjusting the potential of the cover electrode (15) to a value which is substantially constant over the region of the cover electrode such that said value falls in a range between a potential of the first zone (11) and a potential of a portion of the semiconductor chip (10) located outside of the first zone (11), said portion having a conductivity type opposite that of the first zone (11), said voltage divider (16) including a voltage divider resistor (16a) having first (19) and second (20) ends, and a tap (16b) connected to the cover electrode (15), the first end (19) of the voltage divider resistor (16a) is connected with the first zone (11); and the second end (20) of the voltage divider resistor (16a) is connected (M1, M2; B1, B2) on said main surface with said portion of the semiconductor chip (10) located outside the first zone (11) and having a conductivity type opposite that of the first zone (11).