Fairchild Korea Semiconductor Ltd.

Min-hwan Kim

Chang-Ki Jeon

Sung-lyong Kim

Young-suk Choi

Jong-jib Kim

In a high voltage integrated circuit, a low voltage region is separated from a high voltage region by a junction termination. A bipolar transistor in the high voltage region is surrounded by an isolation region having a low doping concentration. The use of a low-doped isolation region increases the size of an active region without reduction of a breakdown voltage.

High voltage integrated circuit including bipolar transistor within high voltage island area

In accordance with the present invention, a metal oxide semiconductor (MOS) transistor has a substrate of a first conductivity type. A drift region of a second conductivity type is formed over the substrate. A body region of the first conductivity type is formed in the drift region. A source region of the second conductivity is formed in the body region. A gate extends over a surface portion of the body region and overlaps each of the source region and the body region such that the surface portion of the body region forms a channel region of the transistor. A drain region of the second conductivity type is formed in the drift region. The drain region is laterally spaced from the source region a first predetermined distance. A first buried layer of the first conductivity type extends into the substrate and the drift region. The first buried layer laterally extends between the source and drain regions.

Lateral DMOS transistor having reduced surface field

A high voltage lateral Double diffused Metal Oxide Semiconductor (DMOS) transistor includes a plurality of well regions of a first conductivity type formed to be spaced out within a well region of a second conductivity type between a channel region of the first conductivity type and a drain region of the second conductivity type. Most current is carried through some portions of the well region of the second conductivity type in which the well regions of the first conductivity do not appear so that the current carrying performance of the device is improved. When a bias voltage is applied to the drain region, the well region of the second conductivity type is completely depleted at other portions where the well region of the second conductivity type and the well regions of the first conductivity type alternately appear so that the breakdown voltage of the device can be increased. In addition, since the well region of the second conductivity type can be easily depleted, not only the breakdown voltage can be increased, but also the impurity concentration of the well region of the second conductivity type can be increased. Accordingly, the on-resistance of the device can be decreased.

Growing community of inventors

Boocheon, South Korea

Min-hwan Kim