Monolithic semiconductor device assemblies

A semiconductor device assembly comprising:

• a first portion of a semiconductor substrate;
• a second portion of the semiconductor substrate, the semiconductor substrate excluding a buried oxide layer;
• a first semiconductor device stack disposed on the first portion of the semiconductor substrate;
• a second semiconductor device stack disposed on the second portion of the semiconductor substrate;
• and
• an isolation trench having a dielectric material disposed therein, the isolation trench being disposed:
• between the first portion of the semiconductor substrate and the second portion of the semiconductor substrate;
• and
• between the first semiconductor device stack and the second semiconductor device stack,
• the isolation trench electrically isolating the first portion of the semiconductor substrate from the second portion of the semiconductor substrate, and electrically isolating the first semiconductor device stack from the second semiconductor device stack.

A semiconductor device assembly, comprising:

• a first portion of a semiconductor substrate;
• a second portion of the semiconductor substrate, the semiconductor substrate excluding a buried oxide layer;
• a semiconductor device layer disposed on the first portion of the semiconductor substrate and the second portion of the semiconductor substrate, the semiconductor device layer including:
• a first semiconductor device disposed on the first portion of the semiconductor substrate;
• and
• a second semiconductor device disposed on the second portion of the semiconductor substrate;
• and
• an isolation trench having a dielectric material disposed therein, the isolation trench being disposed:
• between the first portion of the semiconductor substrate and the second portion of the semiconductor substrate,
• the isolation trench electrically isolating the first portion of the semiconductor substrate from the second portion of the semiconductor substrate, the semiconductor device layer excluding the isolation trench.