“removed due to double publication”. The original paper: Journal: Semiconductor Science and Technology Create an alertIssue Volume 15, Number 6 Citation: L S Tan et al 2000 Semicond. Sci. Technol. 15 585 doi: 10.1088/0268-1242/15/6/317 can be accesses at IOP: http://iopscience.iop.org/0268-1242/15/6/317