In a semiconductor component, which has various differently doped layers (2, 3, 4, 5) within a semiconductor substrate, an improvement of the electrical properties is achieved, wherein the thickness of the substrate in the current-carrying region is locally reduced by a deep etch well (10), the original mechanical stability of the semiconductor substrate largely remaining retained.

A high voltage transistor with high speed capability is disposed in a semiconductor body having a thickness greater than about 100 microns. The collector region adjoining one major surface of the semiconductor body has two collector portions: A first collector portion adjoins selected internal portions of the major surface and has an impurity concentration at the major surface of greater than about 8 .times. 10.sup.18 atoms/cm.sup.3. A second collector portion adjoins the major surface at peripheral portions contiguously around the first collector portion and adjoins the first collector portion interior of the body at said internal portions and has a resistivity throughout of greater than 30 ohm-cm. Said second collector portion at said internal portions has a substantially uniform thickness of at least about 30 microns and a reach-through voltage less than the avalanche breakdown voltage thereof, and said second collector portion at said peripheral portions has a thickness at least about 20% greater than the thickness of said second collector portion at said internal portions. Further, the width of the second collector portion at said peripheral portions is greater than 1 and preferably less than 3 times the thickness of the second collector portion at said internal portions. The base region of the transistor adjoins the second collector portion interior of the body and has a minority carrier diffusion length at least an order of magnitude greater than the thickness of the base region at said internal portions. Preferably, the first collector portion laterally circumscribes the emitter region of the transistor by at least the thickness of the second collector portion at the internal portions of the body.

A high frequency bipolar transistor is provided with integral thermally compensated degenerative feedback resistance. The emitter, base and collector regions of the transistor are positioned in an epitaxial layer of a semiconductor body adjoining a major surface with an adjoining substrate portion having an impurity concentration greater than about 1 .times. 10.sup.18 carriers/cm.sup.3. The emitter region adjoins the major surface in at least one strip configuration preferably of width less than about 10 microns, and has an impurity concentration at the major surface of at least about 1 .times. 10.sup.18 carriers/cm.sup.3. The collector region adjoins the substrate portion and the major surface spaced from the emitter region has a thickness of less than about 10 microns at the active portions, and has an impurity concentration therethrough of less than about 1 .times. 10.sup.14 carriers/cm.sup.3. The base region has a thickness of less than 2 microns and an impurity concentration between about 5 .times. 10.sup.14 and 5 .times. 10.sup.17 carriers/cm.sup.3 between the emitter and collector regions in the epitaxial layer and adjoins the major surface at least peripherally of the emitter region. First, second and third metal contacts spaced substantially parallel of strip configurations make separate ohmic contact to the emitter base and collector regions, respectively. A dielectric layer is applied on the major surface at least adjacent the first metal contact, with a conductor layer of strip configuration on the dielectric layer spaced from and extending substantially parallel to the first metal contact. And a degenerative resistor layer on the first contact, the dielectric layer and the conductor layer extends substantially the length of the first metal contact and the conductor layer and makes ohmic contact to both the first metal contact and the conductor layer along the length thereof, while remaining substantially insulated from the second and third metal contacts and the base and collector regions.