A method of forming a substrate contact in a semiconductor device, comprising the steps of providing a semiconductor base substrate (2) having a buried oxide (BOX) layer (4) and a thin active semiconductor layer (103) on the BOX layer (4), forming a trench (104) in the active semiconductor layer (103) and the Box layer (4) to the semiconductor base substrate (2) below, and then depositing another active semiconductor (epitoxial) layer (6) over the remaining active semiconductor layer (103) and in the trench (104) to create the substrate contact. The trench (104) is etched at a location on the wafer corresponding to a scribe lane (106).