Method for making collector arrangement for magnetotransistor
AssigneeMotorola, Inc.
InventorLjubisa Ristic
Life of this patent
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Abstract
A collector arrangement for a magnetotransistor (10, 25, 30) and a method for making the magnetotransistor (10, 25, 30). A portion of a semiconductor substrate (11) is doped to form a base region (13). The base region is doped to form an emitter region (16, 26, 36) and a collector region (17, 27, 37) such that the collector region (17, 27, 37) surrounds and is spaced apart from the emitter region (16, 26, 36). Collector contacts (C.sub.1 -C.sub.8 and C.sub.5 '-C.sub.8 ', C.sub.13 -C.sub.16) are symmetrically formed in the collector region (17, 27, 37). In a three-dimensional magnetotransistor (10, 25) the collector contacts include split-collector contacts (C.sub.5 -C.sub.8 and C.sub.5 '-C.sub.8 ').
Claims20
A method of forming a semiconductor magnetic field sensor, comprising the steps of:
- providing a semiconductor substrate of a first conductivity type, the semiconductor substrate having a principal surface;
- forming a base region of a second conductivity type in the semiconductor substrate, the base region extending from the principal surface into the semiconductor substrate;
- forming an emitter region of the first conductivity type in the base region, the emitter region extending from the principal surface into the base region;
- forming a collector region of the first conductivity type in the base region, the collector region being a continuous structure that is spaced apart from and laterally surrounds the emitter region;
- providing an electrical contact to the base region;
- providing an electrical contact to the emitter region;
- and
- providing a plurality of collector contacts to the collector region, wherein a current flowing into some of the plurality of collector contacts is changed by a first component of a magnetic flux density, and the current flowing into others of the plurality of collector contacts is changed by a second component of the magnetic flux density.
A method for sensing a directional component of a magnetic flux density, comprising the steps of:
- providing a transistor having an emitter region of a first conductivity type, a base region of a second conductivity type, and a continuous collector region of the first conductivity type, wherein the emitter and the collector regions are formed within the base region and the collector region surrounds and is spaced apart from the emitter region;
- forming a plurality of collector contacts which contact the collector region, wherein a first and a second of the plurality of collector contacts are adjacent opposite sides of the emitter region and a third and a fourth of the plurality of collector contacts are adjacent opposite sides of the emitter region;
- applying a magnetic field to the transistor;
- injecting charge carriers from the emitter region through the base region;
- and
- collecting the charge carriers in the collector region, including collecting a first portion of the charge carriers via the first collector contact, collecting a second portion of the charge carriers via the second collector contact, collecting a third portion of the charge carriers via the third collector contact, and collecting a fourth portion of the charge carriers via the fourth collector contact, the first and second portions having a different number of charge carriers in the presence of a first directional component of a magnetic flux density and the third and fourth portions having a different number of charge carriers in the presence of a second directional component of the magnetic flux density.
A method for sensing a directional component of a magnetic flux density, comprising the steps of:
- providing a semiconductor substrate comprising a base region of a first conductivity type, the base region having a base contact region and containing a continuous collector region of a second conductivity type, the continuous collector region surrounding and spaced apart from an emitter region of the second conductivity type;
- forming a plurality of collector contacts in contact with the continuous collector region;
- forming at least one conduction channel for transporting charge carriers to at least one of the plurality of collector contacts;
- and
- injecting charge carriers from the emitter region, through the at least one conduction region, to the continuous collector region, a first portion of the charge carriers collected at a first collector contact of the plurality of collector contacts, a second portion of the charge carriers collected at a second collector contact of the plurality of collector contacts, a third portion of the charge carriers collected at a third collector contact of the plurality of collector contacts, and a fourth portion of the charge carriers collected at a fourth collector contact of the plurality of collector contacts, the first and second portions being of different amounts in the presence of a first directional component of a magnetic flux density, and the third and fourth portions being of different amounts in the presence of a second directional component of the magnetic flux density.
Dependencies are inferred from the claim text.