Silicon germanium heterojunction bipolar transistor multi-fingered structure

Abstract

The invention discloses a silicon germanium heterojunction bipolar transistor multi-fingered structure. The structure consists of a plurality of silicon germanium heterojunction bipolar transistor monomers; and the multi-fingered structure is shown as C / BEBC / BEBC / BEBC / ...C, wherein CBEBC represents one silicon germanium heterojunction bipolar transistor monomer, one collector C is distributed foreach emitter E, and all adjacent collectors C are connected outside the emitters to form a collector surrounding structure surrounding the emitters E. The current collection area of each silicon germanium heterojunction bipolar transistor is formed in an active area, and the bottom periphery is connected with a buried layer; the buried layer surrounds the active area so as to form a surrounding structure; and the inner sides of the buried layer are extended into the active area to be connected with the current collection area, and the inner sides of the buried layer are not connected with each other. By the silicon germanium heterojunction bipolar transistor multi-fingered structure, junction capacitance can be reduced, the current of the collector is more uniform, the current density andoutput resistance of the collector can be reduced, and the frequency characteristic can be improved.

Description

technical field [0001] The invention relates to a semiconductor integrated circuit, in particular to a multi-finger structure of a germanium-silicon heterojunction bipolar transistor. Background technique [0002] In radio frequency applications, higher and higher device characteristic frequencies are required. Although RFCMOS can achieve higher frequencies in advanced process technologies, it is still difficult to fully meet radio frequency requirements. For example, it is difficult to achieve characteristic frequencies above 40GHz, and advanced technology The research and development cost of compound semiconductors is also very high; compound semiconductors can realize very high characteristic frequency devices, but due to the disadvantages of high material cost and small size, and the toxicity of most compound semiconductors, its application is limited. Silicon germanium HBT is a good choice for ultra-high frequency devices. First, it uses the energy band difference betwe...

AI Technical Summary

Problems solved by technology

[0004] This kind of multi-finger structure is mature and reliable, and is widely used, but the main disadvantage is that a large area of ​​buried layer is required in the whole range of multi-finger devices as the connection and lead-out of the collector, which will lead to large junction capacitance and affect the speed of the device.

At the same time, because the entire multi-finger structure has many emitters and few collectors, the current is very concentrated in the buried layer and the collector, so the collector junction must be made very large to prevent the current density from being too large, thus further increasing the capacitance.

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