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US 10,707,336 B1Granted
High-performance lateral BJT with epitaxial lightly doped intrinsic base
AssigneeInternational Business Machines Corporation
InventorsPouya Hashemi, Tak H. Ning, Jeng-Bang Yau
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Abstract
High-performance lateral bipolar junction transistors (BJTs) are provided in which a lightly doped upper intrinsic base region is formed between a lower intrinsic base region and an extrinsic base region. The lightly doped upper intrinsic base region provides two electron paths which contribute to the collector current, IC. The presence of the lightly doped upper intrinsic base region increases the total IC and leads to higher current gain, β, if there is no increase of the base current, IB.
Claims20
A lateral bipolar junction transistor (BJT) comprising:
- a lower intrinsic base region composed of a first semiconductor material of a first conductivity type and located on a surface of a layer that is composed of at least a partially insulating material;
- an emitter region composed of a second semiconductor material of a second conductivity type, opposite the first conductivity type, located laterally adjacent to, and contacting, a first side of the lower intrinsic base region;
- a collector region composed of the second semiconductor material of the second conductivity located laterally adjacent to, and contacting, a second side of the lower intrinsic base region, which is opposite the first side of the lower intrinsic base region;
- an upper intrinsic base region composed of a third semiconductor material of the first conductivity type located on the lower intrinsic base region, wherein the upper intrinsic base region has a lower dopant concentration than the lower intrinsic base region;
- an extrinsic base region composed of a fourth semiconductor material of the first conductivity type located on the upper intrinsic base region, wherein the extrinsic base region has a higher dopant concentration than both the upper and lower intrinsic base regions;
- and
- a metal-containing fill material located on the extrinsic base region.
4 more elements
A method of forming a lateral bipolar junction transistor (BJT), the method comprising:
- forming a sacrificial gate structure on a surface of an intrinsic base layer composed of a first semiconductor material of a first conductivity type, wherein a dielectric spacer is present along a sidewall of the sacrificial gate structure and in both an emitter-side and a collector-side of the sacrificial gate structure;
- creating a notch into the intrinsic base layer that is located on both the emitter-side and the collector-side of the sacrificial gate structure to provide a faceted intrinsic base portion in both the emitter-side and the collector-side;
- forming an emitter region composed of a second semiconductor material of a second conductivity type that is opposite the first conductivity type above the faceted intrinsic base portion that is present in the emitter-side of the sacrificial gate structure and a collector region composed of the second semiconductor material of the second conductivity type above the faceted intrinsic base portion that is present in the collector-side of the sacrificial gate structure;
- forming an interlayer dielectric (ILD) material laterally adjacent to an upper portion of the sacrificial gate structure and on the emitter region and the collector region;
- removing the sacrificial gate structure to create a cavity and to physically expose a surface of a remaining portion of the intrinsic base layer which defines a lower intrinsic base region;
- forming an upper intrinsic base region composed of a third semiconductor material of the first conductivity type in a lower portion of the cavity and on the physically exposed surface of the lower intrinsic base region, wherein the upper intrinsic base region has a lower dopant concentration than the lower intrinsic base region;
- forming an extrinsic base region composed of a fourth semiconductor material of the first conductivity type on the upper intrinsic base region, wherein the extrinsic base region has a higher dopant concentration than both the upper and lower intrinsic base regions;
- and
- forming a metal-containing fill material on the extrinsic base region and within a remaining portion of the cavity.
6 more elements
Dependencies are inferred from the claim text.