Patent ID: 6924535
Filing Date: 2005-08-02
Classification: H01L

Abstract:
1. A semiconductor device comprising: a semiconductor substrate of a first conductivity type; a first triple well formed in the semiconductor substrate, and having a first well of a second conductivity type and a second well of the first conductivity type formed within the first well; a second triple well formed in the semiconductor substrate, and having a third well of the second conductivity type and a fourth well of the first conductivity type formed within the third well; a low breakdown voltage transistor of the second conductivity type formed at the second well of the first triple well; and a high breakdown voltage transistor of the second conductivity type formed at the fourth well of the second triple well, wherein the first well of the first triple well has an impurity concentration higher than an impurity concentration of the third well of the second triple well, the first well of the first triple well is shallower than the third well of the second triple well, and a ratio of the depths between the first well and the third well is about 2 to 6.