A semiconductor device includes a buried epitaxially grown substrate and a silicon on insulator (SOI) layer. The device also includes a buried oxide (BOX) layer between the buried epitaxially grown substrate and the SOI layer, an isolation trench having first width (w1), a contact trench having a second width (w2) and a capacitive trench having a third width (w3). Methods are described that allow the formation of the trenches in a normal process flow.