Ultra-shallow junction depth profile analysis using TOF-SIMS and TXRF

The drive to fabricate ever shallower source/drain and channel junctions in DRAM and microprocessor production constitutes a great challenge for their analytical characterization. Ultra-shallow SIMS profiling requires high depth resolution and a small surface transient region. It also has to account for the interface between the native oxide and the Si bulk. We have investigated the shallow depth profiling capabilities of TOF-SIMS and TXRF. TOF-SIMS is well established for high sensitivity microarea surface analysis. The technique features high mass resolution, high transmission and a parallel mass registration. Depth profiles are performed in the dual beam mode allowing an independent optimization of the analyzing and sputtering ion beam. The application of a low energy SF5+ sputtering ion beam provides depth resolution in the 0.5 nm range and minimizes the width of the near surface transient region. When depth profiling silicon, the oxidation state of the receding surface can be derived from the intensi...