Three terminal magnetic sensor (TTM) having a metal layer formed in-plane and in contact with the base region for reduced base resistance

A magnetic head, comprising:

• a three terminal magnetic (TTM) sensor;
• the TTM having:
• a base region;
• a collector region which is adjacent the base region;
• an emitter region;
• a barrier region which separates the emitter region from the base region;
• an air bearing surface (ABS) plane defined along sides of the base region, the collector region, and the emitter region;
• an insulator layer which is:
• offset from the ABS plane;
• adjacent the collector region and the base region;
• a metal layer which is:
• offset from the ABS plane;
• and
• in-plane and in contact with magnetic materials of the base region.

A disk drive, comprising:

• a magnetic head;
• a slider which carries the magnetic head;
• a write head portion of the magnetic head;
• a read head portion of the magnetic head;
• the read head portion including a three terminal magnetic sensor (TTM);
• the TTM having:
• a base region;
• a collector region which is adjacent the base region;
• an emitter region;
• a barrier region which separates the emitter region from the base region;
• an air bearing surface (ABS) plane defined along sides of the base region, the collector region, and the emitter region;
• an insulator layer which is:
• offset from the ABS plane;
• adjacent the collector region and the base region;
• a metal layer which is:
• offset from the ABS plane;
• and
• in-plane and in contact with magnetic materials of the base region.

A three terminal magnetic sensor (TTM) for a magnetic head, the TTM comprising:,

• a base region;
• a collector region which is adjacent the base region;
• an emitter region having an emitter lead formed thereover;
• a barrier region which separates the emitter region from the base region;
• a sensing plane defined along sides of the base region, the collector region, and the emitter region;
• a metal layer which is:
• offset from the sensing plane;
• in-plane and in contact with the emitter region;
• and
• in contact with the emitter lead.

A disk drive, comprising:

• a magnetic head;
• a slider which carries the magnetic head;
• a write head portion of the magnetic head;
• a read head portion of the magnetic head;
• the read head portion including a three terminal magnetic sensor (TTM);
• the TTM having:
• a base region;
• a collector region which is adjacent the base region;
• an emitter region having an emitter lead formed thereover;
• a barrier region which separates the emitter region from the base region;
• a sensing plane defined along sides of the base region, the collector region, and the emitter region;
• a metal layer which is:
• offset from the sensing plane;
• in-plane and in contact with the emitter region;
• and
• in contact with the emitter lead.