Fig. 2.

Mechanical and electrical responses of noncoplanar stretchable electronics to in-plane strains. (A) Optical images of stretchable, 3-stage CMOS ring oscillators with noncoplanar mesh designs, for stretching along the bridges (x and y). (B) FEM modeling of the strain distributions at the top surface of the circuit (Top) and at the midpoint of the metal layer (Mid.) and bottom surface (Bot.). (C) Electrical characteristics of the oscillators as represented in the time and frequency (Inset) domains in the different strain configurations illustrated in A. Here, 0s and 0e refer to 0% strains at the start and end of the testing, respectively; 17x and 17y refer to 17% tensile strains along the x and y directions indicated in A, respectively. (D) Optical images of stretchable CMOS inverters with noncoplanar mesh designs, for stretching at 45° to the directions of the bridges (x and y). (E) FEM simulations of these motions. (F) Transfer characteristics of the inverters (output voltage, V_out, and gain as a function of input voltage, V_in). The notations 18x and 18y refer to 18% tensile strains along the x and y directions indicated in D, respectively.