Ultra Shallow Depth Profiling by Secondary Ion Mass Spectrometry Techniques

Abstract

Ultra shallow dopant profiles are one of the major challenges for ULSI silicon metrology. Following the ITRS 2002, the 90nm technology node will appear in 2004 along with the maximum drain extension in the range of 15-25 nm for both P-MOS and N-MOS devices. In this frame, a very abrupt junction with a decay length of 4 nm/decade is mandatory. A depth resolution better than 0.7 nm in profiling shallow implanted dopants is consequently required. In this review, after a brief summary on necessities and difficulties of (N-MOS) ultra shallow profiling for the 90 nm technology node, we present a comparison between two Secondary Ions Mass Spectrometry (SIMS) approaches using different instruments (Magnetic Sector and Time of Flight Spectrometers) for the characterization of arsenic ultra shallow profiles. A particular relevance is dedicated to the methodological optimization and data processing, mainly in quantification and depth scale determination. Quantitative SIMS results have been compared with complementary techniques like LEXES, MEIS and RBS. FIGURE 1. Junction depth vs. technology nodes.

GIMPy: a software for the simulation of X‐ray fluorescence and reflectivity of layered materials

“…The arsenic implanted Si wafers have a nominal fluence of 1.0 × 10 14 and 6.0 × 10 14 atoms/cm 2 and were already characterized in a previous work. [32] All the experimental GIXRF, EDXRF, and XRR measurements were collected using a theta-theta Phoenix multipurpose diffractometer (TNX Srl, Italy) equipped with an Mo tube and a parallel beam multilayer optic (AXO, Germany). A solid state Silicon drift detector (Ketek Gmbh, Germany) was mounted at 90°f rom the sample surface.…”

“…GIXRF and XRF measurements were performed with the primary beam impinging along the longer axis of the samples. The arsenic implanted Si wafers have a nominal fluence of 1.0 × 10 14 and 6.0 × 10 14 atoms/cm 2 and were already characterized in a previous work . All the experimental GIXRF, EDXRF, and XRR measurements were collected using a theta–theta Phoenix multipurpose diffractometer (TNX Srl, Italy) equipped with an Mo tube and a parallel beam multilayer optic (AXO, Germany).…”

Nondestructive dose determination and depth profiling of arsenic ultrashallow junctions with total reflection X-ray fluorescence analysis compared to dynamic secondary ion mass spectrometry

“…For the As-implanted samples, the total implanted dose absolute quantification obtained with TXRF can be compared to values obtained with Low Energy Electron-Induced X-ray Emission Spectrometry (LEXES), Rutherford Back Scattering (RBS), and Medium Energy Ion Scattering (MEIS; [6]). …”

“…Impact energy (1 keV) Cs + was used as primary beam, with a 45j angle of incidence; this combination gives good depth resolution, adequate detection limit to measure junction depth at 1 Â 10 18 at/cm 3 of concentration, and it avoids the formation of roughness and the variation of sputtering rate [6]. The primary beam intensity was set at 10 nA, and the ion beam was rastered over a 250 Â 250 Am 2 area.…”

ToF-SIMS 3D Analysis of Thin Films Deposited in High Aspect Ratio Structures via Atomic Layer Deposition and Chemical Vapor Deposition

“…In this part of study, we focus on improving the analysis of the HAR structures by bypassing the obstacles of TSV characterization by ToF-SIMS and using LHAR test structures. ToF-SIMS in dual-beam mode (dynamic mode) is a well-established technique due to its high detection sensitivity for concentration ratio measurements of the dopant materials [19,20]. However, the analysis of these VHAR structures for quantifying dopant concentration is hardly possible.…”