Bonded semiconductor device structures and device structure fabrication processes to obviate the need for SOI wafers in many device fabrication applications are disclosed. In some examples, multiple etch stop layers are formed in situ during fabrication of an active device structure on a bulk semiconductor wafer. The etch stop layers are incorporated into in a layer transfer process to enable very thin high quality active device layers of substantially uniform across-wafer thickness to be separated from bulk semiconductor wafers and bonded to handle wafers. As a result, these examples can produce high-performance and low-power semiconductor devices while avoiding the high cost of SOI wafers.