"As the SiO2 layer 306 is configured to stop the chemical etching process, silicon layer 114B and the semiconductor structure layer 107 remain untouched by the chemical used to etch the initial substrate 308A. The chemical etching may be done by any process to remove the initial substrate 308A. For example, the etching process may be done with chemicals such as acid, hydroxides, and the like, that" . . . .