Advanced silicon substrate products are being developed for the 90 nm node and smaller devices of the future. Nitrogen-doping during Cz-Si crystal growth is a key technology for some of these products, because this facilitates the engineering of defect properties needed for the low temperature processing at 90 nm node and smaller devices. The measurement of bulk [N] is required at the 10¹³-10¹⁴/cm³ range for these advanced silicon substrate products.

The goal of the industry is to develop an FTIR measurement of the bulk [N], but achieving this at the required concentration range and acceptable precision is still a challenge. An ASTM F 2139 test method for the SIMS measurement was approved in 2001, but the actual precision of the measurement needed improvement and the test method was applicable only down to 1×10¹⁴/cm³.