| 摘要 |
PURPOSE:To perform the high withstand voltage of a lateral PNP transistor having good frequency characteristic by forming an impurity density profile near an NPN type transistor in a lateral direction. CONSTITUTION:This lateral PNP type transistor has an N type diffused layer 301 having high impurity density higher than an epitaxial layer 3 around an emitter, and a P type low impurity density layer 501 extending from a collector layer to the N type layer 301. A base width WB is decided by the width of the layer 301. An impurity density profile formed along a-dotted chain line b-b' can be approached to the same profile as an NPN type transistor, and the base width can be reduced to the same degree as the NPN type transistor. Accordingly, the frequency can be improved more than several ten times to fT>=10MHz. Further, since an N type layer 301 can be enhanced in the impurity density from the epitaxial layer, a punch-through can be suppressed to readily perform an increase in the withstand voltage. |
