A horizontal current bipolar transistor comprises a substrate of first conductivity type, defining a wafer plane parallel to said substrate; a collector drift region above said substrate, having a second, opposite conductivity type, forming a first metallurgical pn-junction with said substrate; a collector contact region having second conductivity type above said substrate and adjacent to said collector drift region; a base region comprising a sidewall at an acute angle to said wafer plane, having first conductivity type, and forming a second metallurgical pn-junction with said collector drift region; and a buried region having first conductivity type between said substrate and said collector drift region forming a third metallurgical pn-junction with the collector drift region. An intercept between an isometric projection of said base region on said wafer plane and an isometric projection of said buried region on said wafer plane is smaller than said isometric projection of said base region.

Various particular embodiments include an integrated circuit (IC) structure having: a stack region; and a silicon substrate underlying and contacting the stack region, the silicon substrate including: a silicon region including a doped subcollector region; a set of isolation regions overlying the silicon region; a base region between the set of isolation regions and below the stack region, the base region including an intrinsic base contacting the stack region, an extrinsic base contacting the intrinsic base and the stack region, and an amorphized extrinsic base contact region contacting the extrinsic base; a collector region between the set of isolation regions; an undercut collector-base region between the set of isolation regions and below the base region; and a collector contact region contacting the collector region under the intrinsic base and the collector-base region via the doped subcollector region.

An integrated circuit is formed by providing a heavily doped substrate of a first conductivity type, forming a lightly doped lower epitaxial layer of the first conductivity type over the substrate, implanting dopants of the first conductivity type into the lower epitaxial layer in an area for a shallow component and blocking the dopants from an area for a deep component, forming a lightly doped upper epitaxial layer over the lower epitaxial layer and activating the implanted dopants to form a heavily doped region. The shallow component is formed over the heavily doped region, and the deep component is formed outside the heavily doped region, extending through the upper epitaxial layer into the lower epitaxial layer.

The betas of the bipolar transistors in a BiCMOS semiconductor structure are increased by forming the emitters of the bipolar transistors with two implants: a source-drain implant that forms a first emitter region at the same time that the source and drain regions are formed, and an additional implant that forms a second emitter region at the same time that another region is formed. The additional implant has an implant energy that is greater than the implant energy of the source-drain implant.

A method of forming an IC includes providing a field dielectric in a portion of a semiconductor surface, a bipolar or Schottky diode (BSD) class device area, a CMOS transistor area, and a resistor area. A polysilicon layer is deposited to provide a polysilicon gate area for MOS transistors in the CMOS transistor area, over the BSD class device area, and over the field dielectric for providing a polysilicon resistor in the resistor area. A first mask pattern is formed on the polysilicon layer. Using the first mask pattern, first implanting (I.sub.1) of the polysilicon resistor providing a first projected range (R.sub.P1)<a thickness of the polysilicon layer and second implanting (I.sub.2) providing a second R.sub.P(R.sub.P2), where R.sub.P2>R.sub.P1. I.sub.2 provides a CMOS implant into the semiconductor surface layer in the CMOS transistor area and/or a BSD implant into the semiconductor surface layer in the BSD area.

An integrated circuit includes an NMOS transistor, a PMOS transistor and a vertical bipolar transistor. The vertical bipolar transistor has an intrinsic base with a band barrier at least 25 meV high at a surface boundary of the intrinsic base, except at an emitter-base junction with an emitter, and except at a base-collector junction with a collector. The intrinsic base may be laterally surrounded by an extrinsic base with a higher dopant density than the intrinsic base, wherein a higher dopant density provides the band barrier at lateral surfaces of the intrinsic base. A gate may be disposed on a gate dielectric layer over a top surface boundary of the intrinsic base adjacent to the emitter. The gate is configured to accumulate the intrinsic base immediately under the gate dielectric layer, providing the band barrier at the top surface boundary of the intrinsic base.

A method is provided of forming a bipolar transistor device. The method comprises depositing a collector dielectric layer over a substrate in a collector active region, depositing a dielectric anti-reflective (DARC) layer over the collector dielectric layer, dry etching away a base opening in the DARC layer, and wet etching away a portion of the collector dielectric layer in the base opening to provide an extended base opening to the substrate. The method further comprises performing a base deposition to form a base epitaxy region in the extended base opening and extending over first and second portions of the DARC layer that remains as a result of the dry etching away the base opening in the DARC layer, and forming an emitter region over the base epitaxy region.

In one aspect, a method of fabricating a bipolar transistor device on a wafer includes the following steps. A dummy gate is formed on the wafer, wherein the dummy gate is present over a portion of the wafer that serves as a base of the bipolar transistor. The wafer is doped to form emitter and collector regions on both sides of the dummy gate. A dielectric filler layer is deposited onto the wafer surrounding the dummy gate. The dummy gate is removed selective to the dielectric filler layer, thereby exposing the base. The base is recessed. The base is re-grown from an epitaxial material selected from the group consisting of: SiGe, Ge, and a III-V material. Contacts are formed to the base. Techniques for co-fabricating a bipolar transistor and CMOS FET devices are also provided.

A semiconductor device comprising: a first electrode; a first semiconductor region of a first conductivity type; a second semiconductor region of a second conductivity type; a third semiconductor region of the second conductivity type provided between the first semiconductor region and the second semiconductor region on the first electrode and having a higher carrier concentration of the second conductivity type than the second semiconductor region; a fourth semiconductor region; a fifth semiconductor region; a sixth semiconductor region; a seventh semiconductor region; a gate electrode; a gate insulating layer; and a second electrode provided on the fifth semiconductor region and the seventh semiconductor region.

A method of forming an IC includes providing a field dielectric in a portion of a semiconductor surface, a bipolar or Schottky diode (BSD) class device area, a CMOS transistor area, and a resistor area. A polysilicon layer is deposited to provide a polysilicon gate area for MOS transistors in the CMOS transistor area, over the BSD class device area, and over the field dielectric for providing a polysilicon resistor in the resistor area. A first mask pattern is formed on the polysilicon layer. Using the first mask pattern, first implanting (I.sub.1) of the polysilicon resistor providing a first projected range (R.sub.P1)<a thickness of the polysilicon layer and second implanting (I.sub.2) providing a second R.sub.P (R.sub.P2), where R.sub.P2>R.sub.P1. I.sub.2 provides a CMOS implant into the semiconductor surface layer in the CMOS transistor area and/or a BSD implant into the semiconductor surface layer in the BSD area.