A Novel Sample Preparation Approach for Dopant Profiling of 14 nm FinFET Devices with Scanning Capacitance Microscopy

2020 ◽  
Author(s):  
Nirmal Adhikari ◽  
Phil Kaszuba ◽  
Gaitan Mathieu ◽  
Erik McCullen ◽  
Thom Hartswick ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Low Voltage ◽  
Negative Impact ◽  
Electrical Contact ◽  
Process Models ◽  
Ion Milling ◽  
Cross Sectional ◽  
Scanning Capacitance Microscopy ◽  
Dopant Profiling ◽  
Profile Control

Abstract Three-dimensional device (FinFET) doping requirements are challenging due to fin sidewall doping, crystallinity control, junction profile control, and leakage control in the fin. In addition, physical failure analyses of FinFETs can frequently reach a “dead end” with a No Defect Found (NDF) result when channel doping issues are the suspected culprit (e.g., high Vt, low Vt, low gain, sub-threshold leakage, etc.). In new technology development, the lack of empirical dopant profile data to support device and process models and engineering has had, and continues to have, a profound negative impact on these emerging technologies. Therefore, there exists a critical need for dopant profiling in the industry to support the latest technologies that use FinFETs as their fundamental building block [1]. Here, we discuss a novel sample preparation method for cross-sectional dopant profiling of FinFET devices. Our results show that the combination of low voltage (<500eV), shallow angle (~10 degree) ion milling, dry etching, and mechanical polishing provides an adequately smooth surface (Rq<5Å) and minimizes surface amorphization, thereby allowing a strong Scanning Capacitance Microscopy (SCM) signal representative of local active dopant (carrier) concentration. The strength of the dopant signal was found to be dependent upon mill rate, electrical contact quality, amorphous layer presence and SCM probe quality. This paper focuses on a procedure to overcome critical issues during sample preparation for dopant profiling in FinFETs.

scholarly journals Cross-sectional TEM Sample Preparation for Nanowires or Porous Films Grown on a Substrate

2007 ◽  
Vol 15 (1) ◽  
pp. 44-45
Author(s):  
Chengyu Song
Keyword(s):  
Low Temperature ◽  
Sample Preparation ◽  
Traditional Method ◽  
Sample Surface ◽  
Specimen Preparation ◽  
Air Bubbles ◽  
Ion Milling ◽  
Porous Films ◽  
Cross Sectional ◽  
Single Section

Nanowires or porous films grown on a substrate normally lack mechanical strength, and may be subject to damage during specimen preparation. When we made cross-sectional TEM specimen for this type of sample, we modified the traditional method by covering the sample with epoxy to improve the film strength, and applying single-section ion milling to protect the film from over-milling.The sample surface is first covered with G1 epoxy. We choose G1 for this application because it is relatively thick and cures at low temperature. For samples with a dense-growth of nanowires or a thick porous film, a brief moment in vacuum helps to get rid of the air bubbles in the epoxy. The glue is cured at 100 degree C for 10 minutes, until its color turns to a reddish brown. To remove the excess glue and flatten the surface, the sample is then ground and polished until the glue is less than 0.1 mm thick.

Guidelines for Two-Dimensional Dopant Profiling Using Scanning Capacitance Microscopy

2000 ◽  
Author(s):  
Axel Born ◽  
R. Wiesendanger
Keyword(s):  
Sample Preparation ◽  
Failure Analysis ◽  
Edge Effects ◽  
Two Dimensional ◽  
Stray Capacitance ◽  
Scanning Capacitance Microscopy ◽  
Dopant Profiling ◽  
3D Geometry ◽  
Cv Measurements ◽  
Preparation Techniques

Abstract This paper provides guidance and insights on the use of scanning capacitance microscopy (SCM) in semiconductor failure analysis. It explains why SCM systems are constrained by rigid performance tradeoffs and how CV measurements are affected by large stray capacitance and as well as edge effects associated with the 3D geometry of the sample and probe. It also explains how samples should be prepared and how proper sample preparation techniques combined with optimally selected voltages make it possible to accurately determine doping concentrations, even in p-n junctions.

Cross-Sectional Tem Sample Preparation of Phase-Change Optical Disk by Ion Milling

1997 ◽  
Vol 480 ◽  
Author(s):  
T. Kouzaki ◽  
K. Yoshioka ◽  
E. Ohno
Keyword(s):  
Sample Preparation ◽  
Phase Change ◽  
Polymer Substrate ◽  
Ion Milling ◽  
Cross Sectional ◽  
Milling Method ◽  
Optical Disks ◽  
The Difference ◽  
Argon Ion ◽  
Sectional Structure

AbstractIt is very difficult to prepare cross-sectional TEM samples for phase-change optical disks by conventional argon ion milling because of the difference of ion milling rates between multilayers and the polymer substrate. We have been successful in preparing samples of those optical disks by ion milling method with dissolution of the polymer substrate in advance. The cross-sectional structure was observed more clearly in this method rather than in ultramicrotome method.

A Multi-Step Transmission Electron Microscopy Sample Preparation Technique for Cracked, Heavily Damaged, Brittle Materials

2014 ◽  
Vol 20 (6) ◽  
pp. 1646-1653
Author(s):  
Claire V. Weiss Brennan ◽  
Scott D. Walck ◽  
Jeffrey J. Swab
Keyword(s):  
Sample Preparation ◽  
Brittle Materials ◽  
Ceramic Materials ◽  
Preparation Technique ◽  
Ion Milling ◽  
Cross Sectional ◽  
Multiphase Materials ◽  
Sample Preparation Technique ◽  
Transmission Electron ◽  
Archaeological Materials

AbstractA new technique for the preparation of heavily cracked, heavily damaged, brittle materials for examination in a transmission electron microscope (TEM) is described in detail. In this study, cross-sectional TEM samples were prepared from indented silicon carbide (SiC) bulk ceramics, although this technique could also be applied to other brittle and/or multiphase materials. During TEM sample preparation, milling-induced damage must be minimized, since in studying deformation mechanisms, it would be difficult to distinguish deformation-induced cracking from cracking occurring due to the sample preparation. The samples were prepared using a site-specific, two-step ion milling sequence accompanied by epoxy vacuum infiltration into the cracks. This technique allows the heavily cracked, brittle ceramic material to stay intact during sample preparation and also helps preserve the true microstructure of the cracked area underneath the indent. Some preliminary TEM results are given and discussed in regards to deformation studies in ceramic materials. This sample preparation technique could be applied to other cracked and/or heavily damaged materials, including geological materials, archaeological materials, fatigued materials, and corrosion samples.

Local Cross-sectional Profiling of Multilayer Thin Films with an Atomic Force Microscope for Layer Thickness Determination

1997 ◽  
Vol 12 (8) ◽  
pp. 1935-1938 ◽  
Author(s):  
J. R. LaGraff ◽  
J. M. Murduck
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Sample Preparation ◽  
Atomic Force Microscope ◽  
A Priori ◽  
Ion Milling ◽  
Cross Sectional ◽  
Atomic Force ◽  
The Individual ◽  
Additional Sample

A new essentially nondestructive cross-sectional method is described for measuring the individual thicknesses of multilayer YBa2Cu3O7 (YBCO) and SrTiO3 (STO) thin films using off-axis ion milling and the atomic force microscope (AFM). Since the ion-milling is done during routine patterning of a thin-film device and the AFM requires only a small area for imaging, no additional sample preparation is required. This is a significant improvement over traditional cross-sectional techniques which often require lengthy and destructive sample preparation. Also, there is no a priori reason that this technique would not be amenable to other multilayer thin-film systems.

A sample preparation technique for cross-sectional AEM of thin films on hard materials

1991 ◽  
Vol 49 ◽  
pp. 1112-1113
Author(s):  
Kim Ostreicher ◽  
Changmo Sung
Keyword(s):  
Sample Preparation ◽  
Protective Coatings ◽  
Ion Beam ◽  
Preparation Technique ◽  
Tungsten Carbides ◽  
Ion Milling ◽  
Cross Sectional ◽  
Hard Materials ◽  
Thin Electron ◽  
Coating Matrix

Hard materials such as tungsten carbides which contain ceramic protective coatings (from 30 nm to several microns in thickness) present unique electron-transparent sample preparation challenges for TEM observations. A cross-sectional sample would allow one to observe the coating, matrix and related interface between the two. Variations in the hardness as well as differences in the compositions of the coating and substrate make this preparation more difficult. Discs of the material cannot simply be core drilled out and mechanically or ion beam prepared since it is the surface or edge of the material containing the coating which must be retained. Ion milling also causes preferential removal of one phase in relation to others leaving a sample which is not uniformly thin or truly representative of the microstructure. A preparation technique used for many semiconductor materials involves gluing together pieces with surface layers or coatings thus forming a stack which can be further processed to yield thin, electron transparent specimens.

Novel Sample Preparation Methods for Transmission Electron Microscopy Observation of Dopant Profiles in Silicon Devices

1999 ◽  
Vol 5 (S2) ◽  
pp. 916-917
Author(s):  
Salvatore Pannitteri
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sample Preparation ◽  
Ion Milling ◽  
Final Thickness ◽  
Cross Sectional ◽  
Silicon Devices ◽  
First Case ◽  
Transmission Electron ◽  
Dopant Profiles

I present details of novel sample preparation techniques used for delineating two-dimensional dopant profiles in silicon devices. These techniques are based on selective chemical etch of doped silicon in a mixture of hydrofluoric and nitric acid, or simply in buffered HF. The altered topography of the etched surface is imaged by transmission electron microscopy (TEM). Two different strategies will be presented by focusing on their sensitive, resolution, and field of application.In the first case the silicon device is subjected to the conventional thinning procedure for TEM observations in cross-sectional configuration. The final thickness is obtained by Ar ion milling and it can vary between 50 to 500 nm. Sample is then immersed in a chemical solution containing HF (40%), HN03 (65%), and CH3COOH (95%) in the ratio 1:10:10. In presence of an intense illumination this mixture preferentially etches those device regions which are doped with boron, while in order to delineate n-type regions, the etching procedure must be performed in the dark.

TEM characterization of silicon epitaxial layer grown on Si-TaS2, eutectic composites

1991 ◽  
Vol 49 ◽  
pp. 802-803
Author(s):  
C.M. Sung ◽  
M. Levinson ◽  
M. Tabasky ◽  
K. Ostreicher ◽  
B.M. Ditchek
Keyword(s):  
Substrate Surface ◽  
Bulk Sample ◽  
Surface Cleaning ◽  
Native Oxide ◽  
Czochralski Growth ◽  
Ion Milling ◽  
Cross Sectional ◽  
Cleaning Methods ◽  
Field Emission Cathodes

Directionally solidified Si/TaSi2 eutectic composites for the development of electronic devices (e.g. photodiodes and field-emission cathodes) were made using a Czochralski growth technique. High quality epitaxial growth of silicon on the eutectic composite substrates requires a clean silicon substrate surface prior to the growth process. Hence a preepitaxial surface cleaning step is highly desirable. The purpose of this paper is to investigate the effect of surface cleaning methods on the epilayer/substrate interface and the characterization of silicon epilayers grown on Si/TaSi2 substrates by TEM.Wafers were cut normal to the <111> growth axis of the silicon matrix from an approximately 1 cm diameter Si/TaSi2 composite boule. Four pre-treatments were employed to remove native oxide and other contaminants: 1) No treatment, 2) HF only; 3) HC1 only; and 4) both HF and HCl. The cross-sectional specimens for TEM study were prepared by cutting the bulk sample into sheets perpendicular to the TaSi2 fiber axes. The material was then prepared in the usual manner to produce samples having a thickness of 10μm. The final step was ion milling in Ar+ until breakthrough occurred. The TEM samples were then analyzed at 120 keV using the Philips EM400T.

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