Patent ID: 6489653
Filing Date: 2002-12-03
Classification: H01L

Abstract:
A semiconductor device having a lateral high-breakdown-voltage transistor comprising:a first-conductivity-type semiconductor substrate; a second-conductivity-type buried layer formed in the semiconductor substrate; a second-conductivity-type epitaxial layer formed on the buried layer; a first-conductivity-type well layer formed in a surface portion of the epitaxial layer; a second-conductivity-type source region formed in a surface portion of the well layer; a second-conductivity-type drain region formed in a surface portion of the epitaxial layer or the well layer, separated from the source region; a second-conductivity-type deep diffusion layer formed in the drain region but extending to a level lower than a bottom of the drain region in contact with the buried layer, and having a higher impurity concentration than the drain region; a gate electrode formed above the well layer between the drain region and the source region, insulated from the well layer; a first drain electrode formed on the deep diffusion layer and electrically connected to the drain region via the deep diffusion layer; a source electrode formed on and electrically connected to the source region; a second-conductivity-type isolating diffusion layer surrounding the drain region and the source region, separated from the well layer, and extending to the buried layer; and a second drain electrode formed on the isolating diffusion layer and electrically connected to the first drain electrode, a distance between the deep diffusion layer and the source region being greater than a thickness of the epitaxial layer on the buried layer.