Silicon-germanium heterojunction bipolar transistor and manufacturing method

Abstract

The invention discloses a silicon-germanium heterojunction bipolar transistor. A collector region consists of a global collector region and a local collector region, and is in contact with a pseudo buried layer. A base region is composed of a P-type silicon-germanium epitaxial layer formed on the surface of the collector region. An emitter region is composed of N-type polycrystalline silicon formed on the base region, and the N-type polycrystalline silicon consists of bottom polycrystalline silicon and top polycrystalline silicon. The local collector region and the emitter region window of thebottom polycrystalline silicon adopt the same photolithography definition to realize complete alignment of the local collector region and the bottom polycrystalline silicon. Before ion implantation in an outer base region, an emitter region window dielectric layer is removed. The ion implantation at a dip angle in the outer base region is self-aligned with the side of the bottom polycrystalline silicon, which increases the doping of an overlapping outer base region which is located outside the bottom polycrystalline silicon and covered by the top polycrystalline silicon and reduces the resistance of the base region. The invention further discloses a manufacturing method of the silicon-germanium heterojunction bipolar transistor. The characteristic frequency and the highest oscillation frequency of devices can be simultaneously improved. The silicon-germanium heterojunction bipolar transistor is applicable to the ultrahigh-frequency application requirement of devices, and is of low process cost.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuit manufacturing, in particular to a silicon-germanium (SiGe) heterojunction bipolar transistor (HBT); the invention also relates to a method for manufacturing the silicon-germanium heterojunction bipolar transistor. Background technique [0002] UHF RF applications require improved characteristic frequency (F t ) and the highest oscillation frequency (F max ). The characteristic frequency is also called the cut-off frequency, which is the frequency when the current gain is 1; the highest oscillation frequency is the frequency when the power gain is 1. [0003] The fully self-aligned SiGe HBT manufacturing process can obtain a very high characteristic frequency and the highest oscillation frequency, but the manufacturing process is complex and requires a selective SiGe epitaxial process. [0004] Such as figure 1 Shown is a schematic diagram of the existing germanium-silicon hetero...

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Problems solved by technology

The increased size of the local collector region 105 increases the collector region capacitance, which is not conducive to F t increase

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