Electrical transmission or interconnection systems – Nonlinear reactor systems – Parametrons
Patent
1983-08-08
1986-10-21
Edlow, Martin H.
Electrical transmission or interconnection systems
Nonlinear reactor systems
Parametrons
357 52, 357 51, 307315, H01L 2702, H01L 2934, H03K 326
Patent
active
046188754
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND
The invention relates generally to a Darlington transistor circuit, and more particularly to a monolithic integrated version thereof.
Circuits of this kind are already known. However, they have the disadvantage that electrical fields acting upon them from outside, such as are produced by the polarization of photoresist coatings during operation at high voltage and temperature, can cause the degradation of blocking-state characteristic curves, or else that the breakdown voltage can be influenced within certain limits only by varying the thickness of the passivation layer but is not variable after the metallizing coating has been applied.
THE INVENTION
Briefly, the Darlington transistor circuit according to the invention features a cover electrode over the doped semiconductor material and a passivation layer insulating the cover electrode from the semiconductor junctions and has the advantage over the prior art that the space charge zone forming around the first and second zones during operation is limited to inside the annular zone serving as a stop ring and underneath the cover electrode is shielded from external electrical fields. A further advantage is that the breakdown voltage at the first and second p-n junctions is variable within wide limits. Providing indirect connections between the cover electrode, a common collector portion of the semiconductor material, and one of the base zones in the semiconductor material affords a particularly simple opportunity for realizing the setting of this breakdown voltage with the aid of a voltage divider. Particularly advantageous further developments of the subject of claims 1 and 2 are disclosed in the further dependent claims 3-12.
DRAWING
Exemplary embodiments of the Darlington transistor circuit according to the invention are shown in the drawing and explained in greater detail in the ensuing description. Shown are:
FIG. 1, the electrical circuit diagram of a known Darlington transistor circuit comprising two n-p-n transistors;
FIG. 2, a section taken through the layout of a Darlington transistor circuit according to FIG. 1;
FIG. 3, a partial section through a Darlington transistor circuit according to the invention, having an external ohmic voltage divider for adjusting the breakdown voltage at the first and second p-n junctions;
FIG. 4, the breakdown voltage U.sub.Br at the first p-n junction in accordance with the divider ratio of this external voltage divider;
FIG. 5, a plan view on a Darlington transistor circuit according to the invention, in which the ohmic voltage divider is monolithically integrated, having closed contact windows;
FIG. 6, a plan view on the disposition of FIG. 5, but with opened contact windows;
FIG. 7, a section taken along the line A-A' of FIG. 6;
FIG. 8, a plan view on a portion of a Darlington transistor circuit according to the invention, in which the ohmic voltage divider is partially replaced by a chain of Zener diodes; and
FIG. 9, a section taken along the line B-B' of FIG. 8.
DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
FIG. 1 shows the electrical circuit diagram of a Darlington transistor circuit having an n-p-n power transistor T.sub.1 and an n-p-n driver transistor T.sub.2 and with respective resistors R.sub.1 and R.sub.2 parallel to the emitter-base paths of these two transistors.
In FIG. 2, a section through the layout of a Darlington transistor circuit according to FIG. 1 is shown. In the common n-conductive semiconductor substrate 10, the two p-conductive base zones 11a and 11b of the two transistors T.sub.1, T.sub.2 are diffused in from a main surface. These zones, together with the semiconductor substrate 10, form p-n junctions 12a and 12b. From the same main surface, the corresponding n-conductive emitter zones 9a and 9b of the two transistors T.sub.1, T.sub.2 are diffused into the zones 11a and 11b. A passivation layer 13 covers those parts of this main surface at which p-n junctions meet the surface. The external connections of the Darlington transistor circuit are marked E, B and C, as in FIG. 1,
REFERENCES:
patent: 3243669 (1966-03-01), Sah
patent: 3510735 (1970-05-01), Potter
patent: 3845495 (1974-10-01), Cauge et al.
patent: 3858235 (1974-12-01), Schild
patent: 4037245 (1977-07-01), Ferro
patent: 4106048 (1978-08-01), Khajezadeh
patent: 4157563 (1979-06-01), Bosselaar
patent: 4167748 (1979-09-01), D'Angelo et al.
patent: 4312011 (1982-01-01), Kanbayashi
patent: 4437107 (1984-03-01), Jonsson et al.
patent: 4482911 (1984-11-01), Quoirin
patent: 4564771 (1986-01-01), Flohrs
Novel IC Structure for 150V High-Voltage Consumer IC, Ichiro Imaizumi et al--8087 IEEE Trans. on Consumer Electronics, Vol. CE-26, (1980), Aug., No. 3, New York, USA, pp. 367-374.
Edlow Martin H.
Henn Terri M.
Robert & Bosch GmbH
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