Bipolar junction transistor with multiple emitter fingers
Bipolar junction transistors and design structures for a bipolar junction transistor. The bipolar junction transistor may include a plurality of emitters that are arranged in distinct emitter fingers. A silicide layer is formed that covers an extrinsic base layer of the bipolar junction transistor and that fills the gaps between adjacent emitters. Non-conductive spacers on the emitter sidewalls electrically insulate the emitters from the silicide layer. The emitters extend through the extrinsic base layer and the silicide layer to contact the intrinsic base layer. The emitters may be formed using sacrificial emitter pedestals in a replacement-type process.
1. A bipolar junction transistor comprising:
an intrinsic base layer;
a silicide layer;
an extrinsic base layer vertically between the intrinsic base layer and the silicide layer;
a first emitter extending through the silicide layer and the extrinsic base layer to the intrinsic base layer;
a second emitter extending through the silicide layer and the extrinsic base layer to the intrinsic base layer, the first emitter and the second emitter having a first end-to-end arrangement in a first emitter finger;
a third emitter and a fourth emitter having a second end-to-end arrangement in a second emitter finger;
a first plurality of non-conductive spacers surrounding the first emitter and extending through the silicide layer and the extrinsic base layer to the intrinsic base layer; and
a second plurality of non-conductive spacers surrounding the second emitter and extending through the silicide layer and the extrinsic base layer to the intrinsic base layer,
wherein the first emitter finger and the second emitter finger are juxtaposed in a side-by-side arrangement, a first portion of the silicide layer is positioned in a gap between the first non-conductive spacers and the second non-conductive spacers, the first portion of the silicide layer directly contacts the first non-conductive spacers, and the first portion of the silicide layer directly contacts the second non-conductive spacers.
2. The bipolar junction transistor of claim 1 wherein the intrinsic base layer is formed on a top surface of a device region, the intrinsic base layer includes a raised region that is elevated relative to the top surface of the device region, and the first emitter and the second emitter directly contact the raised region of the intrinsic base layer.
3. The bipolar junction transistor of claim 2 further comprising:
a plurality of shallow trench isolation regions defining the device region, the shallow trench isolation regions circumscribing the raised region of the intrinsic base layer.
4. The bipolar junction transistor of claim 2 further comprising:
a collector in the device region and aligned with the raised region of the intrinsic base layer, the collector comprised of a first semiconductor material having an opposite conductivity type than the intrinsic base layer.
5. The bipolar junction transistor of claim 1 wherein the first portion of the silicide layer is positioned between the first emitter and third emitters and between the second and fourth emitters, and the silicide layer includes a second portion positioned between the first and second emitters and between the third and fourth emitters.