Patent ID: 6562547
Filing Date: 2003-05-13
Classification: H01L

Abstract:
A method for producing structures in chips to form a bipolar transistor by applying a sequence of structuring steps in a self-adjusting manner, which method comprises the steps of:providing a substrate (8) having an intrinsic base region (9) on a substrate surface; forming a first masking structure (11) covering the intrinsic base region (9) and projecting beyond said substrate surface; performing a first structuring step, in which said first masking structure (11) is used as a mask for doping exposed regions on said substrate surface to form extrinsic base surface regions (10); applying an auxiliary layer (14) comprised of silicon oxide to cover said first masking structure (11) and said extrinsic base regions (10) so as to obtain a formed structure; at least partially denuding said formed structure by planarizing the auxiliary layer (14) to expose the first masking structure (11) to form a second masking structure; and using said second masking structure as a mask for a further structuring step in which a collector region in the substrate, below the intrinsic base region, is selectively doped.