A highly balanced reverse on-chip capacitor pair structure

Abstract

The invention discloses a reverse on-chip capacitor pair structure with high balance, which comprises a pair of capacitor units arranged in reverse direction. Because capacitors are widely used in matching networks in millimeter-wave circuits, the asymmetry of capacitors affects the characteristics of matching networks. On-chip transformers, as common devices in differential circuits, are sensitive to the asymmetry of capacitors. The invention solves the asymmetry caused by the parasitic effect of the substrate and the like under the millimeter wave and higher frequency bands of the traditional single MOM capacitor, greatly improves the symmetry of the capacitor as a two-port passive device, and improves the balance of the passive network including the on-chip transformer. The invention has two connection modes of parallel connection and series connection, and has higher expansibility. The invention can be combined with on-chip transformer and other components to optimize, improve thebalance of the differential circuit, achieve impedance matching and other functions, thereby improving the millimeter wave and higher frequency circuit performance, including the output power and energy conversion efficiency of the power amplifier.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuits, in particular to a highly balanced reverse on-chip capacitance pair structure. Background technique [0002] With the rapid development of silicon-based semiconductor technology, its cut-off frequency and the highest power transmission frequency have exceeded 500GHz, comparable to III-V semiconductor technology. In addition, due to the low cost, high flexibility, and integration of digital and analog features of the silicon-based process, the silicon-based millimeter-wave system has become a research hotspot in academia and industry, including the 5G millimeter-wave broadband ultra-high-speed communication system (WRC-19 1.13), W-band long-distance millimeter-wave automotive radar, terahertz imaging technology, etc. However, due to the low substrate resistivity of the silicon-based process and the small spacing between metal layers, there are many parasitic effects. The parasiti...

AI Technical Summary

Problems solved by technology

But as the frequency increases, 1 / jωC par The value decreases, and because the resistivity of the silicon-based semiconductor process substrate is lower, so R sub The value of is also small, so that D eff It is positively correlated with frequency, resulting in different capacitance values ​​for single MOM and MIM capacitors from the two ports.

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