Semiconductor device and its forming method

Abstract

The present invention relates to a device structure that comprises a substrate with front and back surfaces, and at least one semiconductor device with a first conductive structure located in the substrate and a second conductive structure located thereover. A first conductive contact is located over the front surface of the substrate and laterally offset from the first conductive structure. The first conductive contact is electrically connected to the first conductive structure by a conductive path that extends: (1) from the first conductive structure through the substrate to the back surface, (2) across the back surface, and (3) from the back surface through the substrate to the first conductive contact on the front surface. Further, a second conductive contact is located over the front surface and is electrically connected to the second conductive structure. The conductive path can be formed by lithography and etching followed by metal deposition.

Description

technical field [0001] The present invention generally relates to semiconductor device structures. More particularly, the present invention relates to bipolar device structures having back contacts for improved heat dissipation and reduced parasitic resistance. Background technique [0002] Bipolar junction transistors (BJTs) and varactors (varactors) are playing an increasingly important role in the semiconductor industry. Bipolar circuit performance, especially the improvement of operating speed is the basic requirement to improve the network communication system and wireless system. BJTs with silicon-germanium bases provide ideal device performance for such systems. For example, a current cut-off frequency (f t ). [0003] As the current density in bipolar circuits increases, the heat dissipation and parasitic resistance of bipolar devices create more significant limitations on device performance. High junction temperature and collector resistance make f t decreases...

AI Technical Summary

Problems solved by technology

The total parasitic resistance of conventional bipolar devices is significant because of the relatively high resistance of the semiconductor material forming the above-mentioned conductive paths in conventional bipolar devices, thus increasing with the device cut-off frequency (f t ) increases, the maximum oscillation frequency of the bipolar device (f max ) to limit

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