Visualization of different carrier concentrations in n-type-GaN semiconductors by phase-shifting electron holography with multiple electron biprisms

Microscopy ◽  
2019 ◽  
Vol 69 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Kazuo Yamamoto ◽  
Kiyotaka Nakano ◽  
Atsushi Tanaka ◽  
Yoshio Honda ◽  
Yuto Ando ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Phase Shifting ◽  
Active Layer Thickness ◽  
Electron Holography ◽  
Wide Field ◽  
Transmission Electron ◽  
Dopant Level ◽  
Phase Profile ◽  
Phase Resolution

Abstract Phase-shifting electron holography (PS-EH) using a transmission electron microscope (TEM) was applied to visualize layers with different concentrations of carriers activated by Si (at dopant levels of 1019, 1018, 1017 and 1016 atoms cm−3) in n-type GaN semiconductors. To precisely measure the reconstructed phase profiles in the GaN sample, three electron biprisms were used to obtain a series of high-contrast holograms without Fresnel fringes generated by a biprism filament, and a cryo-focused-ion-beam (cryo-FIB) was used to prepare a uniform TEM sample with less distortion in the wide field of view. All layers in a 350-nm-thick TEM sample were distinguished with 1.8-nm spatial resolution and 0.02-rad phase-resolution, and variations of step width in the phase profile (corresponding to depletion width) at the interfaces between the layers were also measured. Thicknesses of the active and inactive layers at each dopant level were estimated from the observed phase profile and the simulation of theoretical band structure. Ratio of active-layer thickness to total thickness of the TEM sample significantly decreased as dopant concentration decreased; thus, a thicker TEM sample is necessary to visualize lower carrier concentrations; for example, to distinguish layers with dopant concentrations of 1016 and 1015 atoms cm−3. It was estimated that sample thickness must be more than 700 nm to make it be possible to detect sub-layers by the combination of PS-EH and cryo-FIB.

Phase-Shifting Electron Holography for Accurate Measurement of Potential Distributions in Organic and Inorganic Semiconductors

Microscopy ◽  
2020 ◽  
Author(s):  
Kazuo Yamamoto ◽  
Satoshi Anada ◽  
Takeshi Sato ◽  
Noriyuki Yoshimoto ◽  
Tsukasa Hirayama
Keyword(s):  
High Performance ◽  
Focused Ion Beam ◽  
Phase Measurement ◽  
Ion Beam ◽  
Functional Materials ◽  
Phase Shifting ◽  
Future Research ◽  
Electron Holography ◽  
Preparation Technique ◽  
Inorganic Semiconductors

Abstract Phase-shifting electron holography (PS-EH) is an interference transmission electron microscopy technique that accurately visualizes potential distributions in functional materials, such as semiconductors. In this paper, we briefly introduce the features of the PS-EH that overcome some of the issues facing the conventional EH based on Fourier transformation. Then, we present a high-precision PS-EH technique with multiple electron biprisms and a sample preparation technique using a cryo-focused-ion-beam, which are important techniques for the accurate phase measurement of semiconductors. We present several applications of PS-EH to demonstrate the potential in organic and inorganic semiconductors and then discuss the differences by comparing them with previous reports on the conventional EH. We show that in situ biasing PS-EH was able to observe not only electric potential distribution but also electric field and charge density at a GaAs p-n junction and clarify how local band structures, depletion layer widths, and space charges changed depending on the biasing conditions. Moreover, the PS-EH clearly visualized the local potential distributions of two-dimensional electron gas (2DEG) layers formed at AlGaN/GaN interfaces with different Al compositions. We also report the results of our PS-EH application for organic electroluminescence (OEL) multilayers and point out the significant potential changes in the layers. The proposed PS-EH enables more precise phase measurement compared to the conventional EH, and our findings introduced in this paper will contribute to the future research and development of high-performance semiconductor materials and devices.

Direct Transmission Electron Microscope Observations of Doping Variations in InP-Based Semiconductor Laser Diodes

1998 ◽  
Vol 4 (S2) ◽  
pp. 648-649 ◽  
Author(s):  
R. Hull
Keyword(s):  
Electron Microscopy ◽  
Spatial Resolution ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Electron Holography ◽  
Semiconductor Doping ◽  
System A ◽  
Transmission Electron ◽  
Semiconductor Laser Diodes ◽  
Secondary Ion

The ability to map semiconductor doping distributions with high spatial resolution (∽10 nm) and high compositional sensitivity (of order 1 ppm) is of enormous importance to the microelectronics and optoelectronics industry. Although several methods (e.g. scanning capacitance microscopy, masked secondary ion mass spectroscopy, secondary electron microscopy, electron holography) are under development, no technique currently offers the combination of sufficient resolution, sensitivity and reproducibility to fully address characterization requirements. In this paper, we describe development of a technique which utilizes focused ion beam (FIB) sputtering and transmission electron microscopy (TEM) to enable direct imaging of dopant distributions in InP-based semiconductor devices, with spatial resolution of order 10 - 30 ran, and compositional sensitivity of order 1017 cm-3 (i.e. 5 ppm).Laser diode samples are prepared for TEM imaging using a FEI 200 30 kV Ga+ focused ion beam system. A schematic of the relevant structure is shown in Figure 1(a).

Off-Axis Electron Holography of Unbiased and Reverse-Biased Focused Ion Beam Milled Sip-nJunctions

2005 ◽  
Vol 11 (1) ◽  
pp. 66-78 ◽  
Author(s):  
Alison C. Twitchett ◽  
Rafal E. Dunin-Borkowski ◽  
Robert J. Hallifax ◽  
Ronald F. Broom ◽  
Paul A. Midgley
Keyword(s):  
Electrostatic Potential ◽  
Reverse Bias ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Specimen Preparation ◽  
Electron Holography ◽  
Thin Sample ◽  
Transmission Electron ◽  
Milled Sample

Off-axis electron holography is used to measure electrostatic potential profiles across a siliconp-njunction, which has been prepared for examination in the transmission electron microscope (TEM) in two different specimen geometries using focused ion beam (FIB) milling. Results are obtained both from a conventional unbiased FIB-milled sample and using a novel sample geometry that allows a reverse bias to be applied to an FIB-milled samplein situin the TEM. Computer simulations are fitted to the results to assess the effect of TEM specimen preparation on the charge density and the electrostatic potential in the thin sample.

Low Energy Ar Ion Milling of FIB TEM Specimens from 14 nm and Future FinFET Technologies

2018 ◽  
Author(s):  
C.S. Bonifacio ◽  
P. Nowakowski ◽  
M.J. Campin ◽  
M.L. Ray ◽  
P.E. Fischione
Keyword(s):  
Field Effect Transistor ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Specimen Preparation ◽  
Ion Milling ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Effect Transistor ◽  
20 Nm ◽  
Argon Ion

Abstract Transmission electron microscopy (TEM) specimens are typically prepared using the focused ion beam (FIB) due to its site specificity, and fast and accurate thinning capabilities. However, TEM and high-resolution TEM (HRTEM) analysis may be limited due to the resulting FIB-induced artifacts. This work identifies FIB artifacts and presents the use of argon ion milling for the removal of FIB-induced damage for reproducible TEM specimen preparation of current and future fin field effect transistor (FinFET) technologies. Subsequently, high-quality and electron-transparent TEM specimens of less than 20 nm are obtained.

TEM Sample Preparation Tricks for Advanced DRAMs

2015 ◽  
Author(s):  
Ching Shan Sung ◽  
Hsiu Ting Lee ◽  
Jian Shing Luo
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sample Preparation ◽  
Integrated Circuit ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Tem Analysis ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Characterization Of Materials

Abstract Transmission electron microscopy (TEM) plays an important role in the structural analysis and characterization of materials for process evaluation and failure analysis in the integrated circuit (IC) industry as device shrinkage continues. It is well known that a high quality TEM sample is one of the keys which enables to facilitate successful TEM analysis. This paper demonstrates a few examples to show the tricks on positioning, protection deposition, sample dicing, and focused ion beam milling of the TEM sample preparation for advanced DRAMs. The micro-structures of the devices and samples architectures were observed by using cross sectional transmission electron microscopy, scanning electron microscopy, and optical microscopy. Following these tricks can help readers to prepare TEM samples with higher quality and efficiency.

Focused Ion Beam Analysis of Low-K Dielectrics

2000 ◽  
Author(s):  
H. J. Bender ◽  
R. A. Donaton
Keyword(s):  
Electron Microscope ◽  
Cross Section ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Single Step ◽  
Specimen Preparation ◽  
Transmission Electron ◽  
Beam Analysis ◽  
Low K ◽  
Scanning Electron

Abstract The characteristics of an organic low-k dielectric during investigation by focused ion beam (FIB) are discussed for the different FIB application modes: cross-section imaging, specimen preparation for transmission electron microscopy, and via milling for device modification. It is shown that the material is more stable under the ion beam than under the electron beam in the scanning electron microscope (SEM) or in the transmission electron microscope (TEM). The milling of the material by H2O vapor assistance is strongly enhanced. Also by applying XeF2 etching an enhanced milling rate can be obtained so that both the polymer layer and the intermediate oxides can be etched in a single step.

Fin Level Defect Isolation Inside a FinFET Using Electron Beam Alteration of Current Flow

2017 ◽  
Author(s):  
H.J. Ryu ◽  
A.B. Shah ◽  
Y. Wang ◽  
W.-H. Chuang ◽  
T. Tong
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Focused Ion Beam ◽  
Current Flow ◽  
Ion Beam ◽  
The Body ◽  
Complete Understanding ◽  
Root Cause ◽  
Transmission Electron ◽  
Defect Isolation

Abstract When failure analysis is performed on a circuit composed of FinFETs, the degree of defect isolation, in some cases, requires isolation to the fin level inside the problematic FinFET for complete understanding of root cause. This work shows successful application of electron beam alteration of current flow combined with nanoprobing for precise isolation of a defect down to fin level. To understand the mechanism of the leakage, transmission electron microscopy (TEM) slice was made along the leaky drain contact (perpendicular to fin direction) by focused ion beam thinning and lift-out. TEM image shows contact and fin. Stacking fault was found in the body of the silicon fin highlighted by the technique described in this paper.

Transmission Electron Microscopy (TEM) Specimen Preparation Technique using Focused Ion Beam (FIB): Application to Material Characterization of Chemical Vapor Deposition of Tungsten (W) and Tungsten Silicides (WSix)

1997 ◽  
Author(s):  
K. Doong ◽  
J.-M. Fu ◽  
Y.-C. Huang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Chemical Vapor ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Transmission Electron

Abstract The specimen preparation technique using focused ion beam (FIB) to generate cross-sectional transmission electron microscopy (XTEM) samples of chemical vapor deposition (CVD) of Tungsten-plug (W-plug) and Tungsten Silicides (WSix) was studied. Using the combination method including two axes tilting[l], gas enhanced focused ion beam milling[2] and sacrificial metal coating on both sides of electron transmission membrane[3], it was possible to prepare a sample with minimal thickness (less than 1000 A) to get high spatial resolution in TEM observation. Based on this novel thinning technique, some applications such as XTEM observation of W-plug with different aspect ratio (I - 6), and the grain structure of CVD W-plug and CVD WSix were done. Also the problems and artifacts of XTEM sample preparation of high Z-factor material such as CVD W-plug and CVD WSix were given and the ways to avoid or minimize them were suggested.

To Eliminate Curtain Effect of FIB TEM Samples by a Combination of Sample Dicing and Backside Milling

2014 ◽  
Author(s):  
Jian-Shing Luo ◽  
Hsiu Ting Lee
Keyword(s):  
Sample Preparation ◽  
Focused Ion Beam ◽  
Preparation Method ◽  
Low Cost ◽  
Ion Beam ◽  
Sample Preparation Method ◽  
Site Specific ◽  
Dual Beam ◽  
Transmission Electron

Abstract Several methods are used to invert samples 180 deg in a dual beam focused ion beam (FIB) system for backside milling by a specific in-situ lift out system or stages. However, most of those methods occupied too much time on FIB systems or requires a specific in-situ lift out system. This paper provides a novel transmission electron microscopy (TEM) sample preparation method to eliminate the curtain effect completely by a combination of backside milling and sample dicing with low cost and less FIB time. The procedures of the TEM pre-thinned sample preparation method using a combination of sample dicing and backside milling are described step by step. From the analysis results, the method has applied successfully to eliminate the curtain effect of dual beam FIB TEM samples for both random and site specific addresses.

A Methodology to Reduce Ion Beam Induced Damage in TEM Specimens Prepared by FIB

2002 ◽  
Author(s):  
Chin Kai Liu ◽  
Chi Jen. Chen ◽  
Jeh Yan.Chiou ◽  
David Su
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sample Preparation ◽  
Integrated Circuit ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Specimen Preparation ◽  
Tem Analysis ◽  
Sensitive Issue ◽  
Transmission Electron

Abstract Focused ion beam (FIB) has become a useful tool in the Integrated Circuit (IC) industry, It is playing an important role in Failure Analysis (FA), circuit repair and Transmission Electron Microscopy (TEM) specimen preparation. In particular, preparation of TEM samples using FIB has become popular within the last ten years [1]; the progress in this field is well documented. Given the usefulness of FIB, “Artifact” however is a very sensitive issue in TEM inspections. The ability to identify those artifacts in TEM analysis is an important as to understanding the significance of pictures In this paper, we will describe how to measure the damages introduced by FIB sample preparation and introduce a better way to prevent such kind of artifacts.

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