Achieve Consistent 80 nm Lamella for DRAM Failure Analysis with TESCAN’s Xe FIB-SEM  

Resolve Ti and Oxide Interfaces in TEM with Xe Plasma FIB-SEM Sample Preparation

SDRAM devices at the 66 nm node feature delicate multilayer stacks where Ti and oxide interfaces must remain intact for accurate failure analysis. Ga FIB prep methods often cause amorphization or ion implantation, which can distort elemental signals and mask structural details critical to root cause evaluation.

Tescan SOLARIS X with iFIB+™ Xe plasma FIB provides a clean, Ga-free alternative for preparing thin lamellae suitable for TEM and EDS. Maintain interface integrity, reduce damage, and produce reliable TEM specimens for confident analysis of sub-100 nm DRAM structures.

Why Prepare TEM Lamellae from SDRAM Devices using Tescan SOLARIS X with Xe Plasma FIB?

Target Specific Memory Cells for Root Cause Failure Analysis

Use Tescan SOLARIS X to precisely prepare TEM lamellae from regions of interest within DRAM devices. Extract intact structures for accurate, site-specific failure diagnostics.

Prepare Stable, Site-Specific Lamellae for Confident Lift-Out

Create clean, uniform lamellae with precise trenching and thinning. Use real-time SEM control to ensure mechanical stability and edge integrity before lift-out.

Secure Lamella Placement for Downstream TEM Inspection

Position and attach lamella reliably using Tescan’s workflow for ex-situ lift-out. Ensure sample stability during transfer and preserve alignment for accurate high-resolution analysis.

Achieve Electron Transparency for High-Resolution DRAM Imaging

Produce sub-100 nm lamellae optimized for TEM and STEM. Maintain uniform thickness and structural clarity across the region of interest for reliable nanoscale inspection.

Visualize Subtle DRAM Features with STEM Bright Field Imaging

Capture fine structural details across gate contacts and dielectric layers. Use high-resolution contrast with electron-transparent lamellae to support precise failure localization.

Contents 

1. Root of the Problem

Why Ga-Based FIB Prep Compromises DRAM Failure Analysis

Sub-100 nm DRAM devices contain delicate gate and capacitor structures that demand precise, low-damage TEM preparation. However, Ga FIB workflows often introduce amorphous damage, ion implantation, and redeposition — particularly in sensitive regions like Ti contacts and oxide interfaces.

These effects degrade image contrast, interfere with EDS signals, and reduce confidence in failure analysis results.

Tescan SOLARIS X with iFIB+™ Xe plasma FIB avoids these limitations by combining inert ion milling with fine beam control and in-situ monitoring.

• Ga-free prep preserves native material chemistry
• Final thinning below 5 keV reduces amorphous surface layers
• Real-time SEM imaging supports immediate lamella QC
• Compatible with BF-STEM, HAADF, and EDS mapping

Avoid rework, reduce artifacts, and confidently localize failures in lamellae prepared from today’s most advanced DRAM technologies.

2. Materials and Methods

How TEM Sample Preparation Was Performed Using Tescan SOLARIS X with Xe Plasma FIB-SEM

A 66 nm SDRAM sample was selected to demonstrate the effectiveness of non-Ga FIB TEM lamella preparation using the Tescan SOLARIS X. The region of interest was first identified with high-resolution SEM imaging to localize gate-level structures and capacitor arrays.

Bulk trenching and lamella lift-out were performed using high-current Xe plasma milling, followed by stepwise thinning to achieve electron transparency. Final thinning was carried out below 5 keV to minimize amorphous damage and preserve critical interface quality.

Lamella quality was verified in-situ using SEM contrast and geometric inspection. The completed sample was mounted ex-situ and imaged using BF-STEM and HAADF detectors. EDS mapping was used to confirm oxide and Ti layer integrity across the thinned region.

The Xe FIB-SEM workflow ensured fast, repeatable, and contamination-free preparation of high-quality TEM specimens from targeted DRAM structures.

3. Results and Discussion

Produce High-Quality Lamella for STEM and EDS Analysis of DRAM Interfaces

Using Tescan SOLARIS X with Xe plasma FIB, a lamella approximately 80 nm thick was prepared from the active region of a 66 nm SDRAM device. In-situ SEM imaging confirmed uniform thinning and edge integrity prior to lift-out.

Post-preparation imaging in BF-STEM and HAADF modes revealed clear resolution of gate structures, dielectric layers, and capacitor contacts. Interface contrast remained high across oxide and Ti regions, with minimal surface damage or curtaining.

EDS mapping confirmed the presence and spatial continuity of key materials, including Ti electrodes and adjacent oxide layers. Spectral data showed no evidence of Ga contamination, supporting the inert milling characteristics of the Xe source.

Together, the results demonstrate that the SOLARIS X workflow delivers electron-transparent lamellae suitable for advanced DRAM failure analysis — with reliable structure preservation, strong elemental contrast, and efficient prep time.