As illustrated in FIG. 1E, in some embodiments, a thickness 145 of the inorganic liftoff layer 110 is deposited so as to be sufficiently large to facilitate getting the horizontal etchant solvent under the metal layer 130 and thereby facilitate an efficient rapid liftoff process. Having too thin of the liftoff layer 110 may result in the etchant solvent not getting under all of the metal layer 130 and consequently, the metal layer 130 may not be lifted off properly and metal flecks can be left on the surface of the softening polymer layer 105.

The target thickness 145 of the liftoff layer will depend on the size, and the thickness, of the metal layer 130 to be removed by the lift-off process. For example, in some embodiments, e.g., when the metal layer 130 has a horizontal dimension in the plane of the softening polymer layer 105 of at least about 400 nm, the inorganic liftoff layer 110 can have a thickness 145 in a range from about 600 nm to 1000 nm, and, in some embodiments, at least about 400 nm thick.

FIGS. 2A-2J and 2L-2M show an example flexible electrical device 200 of the disclosure at intermediate stages of an example manufacturing process of the disclosure with another embodiment of the lift-off process of the disclosure.

FIG. 2A shows the device 200 after forming a thin film electrode trace 140 on a softening polymer layer 105.