US 2016/0240634 A1Published application

Bipolar transistor

AssigneeToyota Jidosha Kabushiki Kaisha

InventorsTakashi OKAWA, Hiroomi EGUCHI, Hiromichi KINPARA, Satoshi IKEDA

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Abstract

Presented is a bipolar transistor capable of improving a current amplification rate while improving voltage resistance. A bipolar transistor is provided with a p-type emitter region, a p-type collector region, an n-type base region located between the emitter region and the collector region, a p-type first embedded region located below the base region, and an n-type region having a lower n-type impurity concentration than the base region. The base region is provided with a first high-concentration region and a low-concentration region positioned above the first embedded region, and a second high-concentration region positioned on a collector region side than the low-concentration region, wherein the second high-concentration region has a higher n-type impurity concentration than the low-concentration region.

Claims6

Dependent claims

A bipolar transistor comprising a semiconductor substrate,

wherein the semiconductor substrate comprises:
a p-type emitter region located in a part of a front surface of the semiconductor substrate;
a p-type collector region located in a part of the front surface of the semiconductor substrate;
an n-type base region located between the emitter region and the collector region in a part of the front surface of the semiconductor substrate;
a p-type first embedded region located below the base region;
and
an n-type region having a lower n-type impurity concentration than the base region, being in contact with the emitter region, the collector region, the base region and the first embedded region, separating the emitter region from the base region and the first embedded region, and separating the collector region from the base region and the first embedded region,
wherein the base region comprises:
a first base region positioned above the first embedded region;
and
a second base region positioned on a collector region side than the first base region, and
the second base region has a higher n-type impurity concentration than the first base region.

9 more elements

Dependencies are inferred from the claim text.