Formation of n+/p junctions less than 20 nm deep in Ge and diffusion control by Flash Lamp Annealing (FLA)

We demonstrate the formation of n+/p ultra-shallow junctions in Ge using Flash Lamp Annealing (FLA). With FLA both shallow junctions and high activation can be achieved, for example, a sheet resistance of 400 ohms/sq with a junction depth of 20 nm. The shallowest junction depth was 17 nm with a sheet resistance of 493 ohms/sq. In addition, by varying the FLA conditions, i.e., the temperature and annealing time in the millisecond range, diffusion lengths of less than 30 nm can be controlled with a precision of 1nm. These results indicate that FLA has great potential for forming ultra-shallow n+/p junctions in Ge devices.