Novel on-chip spiral inductors with back hollow structure

摘要

In this work, on-chip spiral inductors with back hollow structure have been prepared on the 500 mu m thick silicon substrate with high resistivity (P > 5000 Omega cm). The silicon underneath the inductor region has been completely etched by deep etching process in order to reduce the substrate eddy current losses. Several types of square spiral on-chip inductors with different metal width (w) and line spacing (s) in the case of w + s = 40 mu m were fabricated. The experimental results are verified by FEM simulation using HFSS software. The results show that the Q-factor and self-resonance frequency of back hollow structure inductors are both enhanced compared with the conventional inductors. Furthermore, narrower width of coils for the on-chip spiral inductors with back hollow structure can result in higher Q-factor, inductance L and self-resonance frequency, which provide some important design guides for the fabrication of the high performance on-chip inductors.