Abstract: One or more semiconductor arrangements and techniques for forming such semiconductor arrangements are provided. A semiconductor arrangement comprises a channel, such as an un-doped channel, over a substrate. The semiconductor arrangement comprises a gate, such as a gate-all-around structure gate, around the channel. The semiconductor arrangement comprises an isolation structure, such as a silicon germanium oxide structure, between the gate and the substrate. The isolation structure blocks current leakage into the substrate. Because the semiconductor arrangement comprises the isolation structure, the channel can be left un-doped, which improves electron mobility and decreases gate capacitance.