Compound semiconductor layered structures and processes for making the same

A compound semiconductor layered structure comprising:

• i. a silicon carbide semiconductor substrate having a bottom surface and a top surface;
• and
• ii. a silicon carbide semiconductor film bonded on top of said silicon carbide semiconductor substrate, said silicon carbide semiconductor film comprising a bottom layer in direct contact with said top surface of said silicon carbide semiconductor substrate,
• characterized in that said bottom layer is porous and polycrystalline.

Process for preparing a compound semiconductor layered structure, comprising the steps of:

• i. porosifying a single crystalline, compound semiconductor substrate using metal-assisted photochemical etching, thereby obtaining a single crystalline compound semiconductor substrate (S-1) having a porous top surface (S-12, S-13);
• ii. applying a stressor layer onto said porous top surface (S-12, S-13), thereby forming a stressor layer—substrate wafer;
• iii. controlled spalling of a compound semiconductor thin film from said semiconductor substrate using said stressor layer in said stressor layer—substrate wafer, thereby exfoliating a compound semiconductor thin film;
• iv. removing said stressor layer from said compound semiconductor thin film, thereby obtaining an isolated compound semiconductor thin film;
• and
• v. bonding said isolated compound semiconductor thin film onto a polycrystalline semiconductor substrate, thereby obtaining a compound semiconductor layered structure.