Full-Wave Analysis of Inhomogeneous Deep-Trench Isolation Patterning for Substrate Coupling Reduction and $Q$-Factor Improvement

Full-wave analysis of deep-trench isolation patterning (DTP) is presented for substrate coupling reduction and Q-factor improvement. Effects of the buried layer (BL) doping level and grounding mechanisms on substrate coupling are analyzed. Influences of induced depletion regions on substrate coupling are investigated. Q-factor improvement of on-chip RF inductors resulting from the interruption of BLs and part of the lossy substrate by DTP to limit electric and magnetic energy dissipation is studied. The combination of DTP with topological optimization demonstrates high Q-factor enhancement. Distributed capacitances and resistances resulting from the BL and substrate grating are evaluated. Coupling between inductors and limits of representations by lumped-element equivalent circuits to account for distributed effects are discussed. Comparison of obtained results with two-and-one-half- and three-dimensional-based commercial electromagnetic tools and with measurement data for reference structures are presented