US 7,256,433 B2 · Bipolar transistor and a method of manufacturing the same

Abstract

A bipolar transistor having enhanced characteristics is fabricated by etching a base mesa, which is formed below an emitter mesa (upper emitter layer) and a base electrode, so as to have jut regions on the edges of its generally rectangular region. A mask film, e.g., insulating film, is formed to cover the rectangular region and jut regions, and the base layer is etched by use of the insulating film as a mask to form a base mesa. Consequently, abnormal etching can be prevented from occurring along the base electrode and emitter mesa on the edges of the area where the base electrode and emitter mesa confront each other, and an increase in resistance between the base layer and the emitter layer can be prevented, whereby the bipolar transistor can have enhanced characteristics.

Claims15

Dependent claims

A bipolar transistor including a collector, a base and an emitter, said transistor comprising:

(a) a base mesa constituting said base and formed over said collector;
(b) an emitter mesa constituting said emitter and formed over said base mesa;
and
(c) a base electrode formed over said base mesa and extending in a first direction,
(d) said base mesa including a jut region in the direction of extension of said base electrode,
wherein said base electrode has a first side which confronts a second side of said emitter mesa, and
wherein a distance between said first side, at its end immediate to said jut region, and the edge of said jut region is larger than or equal to the height of said base mesa plus 0.3 μm.

4 more elements

A bipolar transistor including a collector, a base and an emitter, said transistor comprising:

(a) a base mesa constituting said base and formed in a first region over said collector and in a jut region which is made contiguously to the first region,
said first region having a first through fourth sides and extending in the directions in which the first and the third sides meet, the third and the second sides meet, the second and the fourth sides meet, and the fourth and the first sides meet;
(b) an emitter mesa constituting said emitter and formed over said base mesa, having a first through fourth emitter mesa sides, and extending in the directions in which the first and the third emitter mesa sides meet, the third and the second emitter mesa sides meet, the second and the fourth emitter mesa sides meet, and the fourth and the first emitter mesa sides meet;
and
(c) a base electrode formed over said base mesa to have a first through fourth base electrode sides and extending in the directions in which the first and the third base electrode sides meet, the third and the second base electrode sides meet, the second and the fourth base electrode sides meet, and the fourth and the first base electrode sides meet,
(d1) the second emitter mesa side confronting the first base electrode side,
(d2) the second side running along the second base electrode side,
(d3) the fourth side extending in the direction to meet the second emitter mesa side, first base electrode side, second side and second base electrode side, and
(d4) said jut region comprised in the first region, in its portion immediate to the fourth side, such that a second distance between the first base electrode side, at its end immediate to the fourth side, or the intersection of the first base electrode side and the fourth side in case these sides intersect, and the edge of said jut region is larger than a first distance between the second base electrode side and the second side.

6 more elements

Dependencies are inferred from the claim text.

Bipolar transistor and a method of manufacturing the same

Life of this patent

Bipolar transistor and a method of manufacturing the same

Life of this patent

Abstract

Claims15