scholarly journals Optimizing performance and yield of vertical GaN diodes using wafer scale optical techniques

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
James C. Gallagher ◽  
Mona A. Ebrish ◽  
Matthew A. Porter ◽  
Alan G. Jacobs ◽  
Brendan P. Gunning ◽  
...  

AbstractTo improve the manufacturing of vertical GaN devices for power electronics applications, the effects of defects in GaN substrates need to be better understood. Many non-destructive techniques including photoluminescence, Raman spectroscopy and optical profilometry, can be used to detect defects in the substrate and epitaxial layers. Raman spectroscopy was used to identify points of high crystal stress and non-uniform conductivity in a substrate, while optical profilometry was used to identify bumps and pits in a substrate which could cause catastrophic device failures. The effect of the defects was studied using vertical P-i-N diodes with a single zone junction termination extention (JTE) edge termination and isolation, which were formed via nitrogen implantation. Diodes were fabricated on and off of sample abnormalities to study their effects. From electrical measurements, it was discovered that the devices could consistently block voltages over 1000 V (near the theoretical value of the epitaxial layer design), and the forward bias behavior could consistently produce on-resistance below 2 mΩ cm2, which is an excellent value considering DC biasing was used and no substrate thinning was performed. It was found that high crystal stress increased the probability of device failure from 6 to 20%, while an inhomogeneous carrier concentration had little effect on reverse bias behavior, and slightly (~ 3%) increased the on-resistance (Ron). Optical profilometry was able to detect regions of high surface roughness, bumps, and pits; in which, the majority of the defects detected were benign. However a large bump in the termination region of the JTE or a deep pit can induce a low voltage catastrophic failure, and increased crystal stress detected by the Raman correlated to the optical profilometry with associated surface topography.

Author(s):  
Terence Kane

Abstract A 300mm wafer atomic force prober (AFP) has been installed into IBM’s manufacturing line to enable rapid, nondestructive electrical identification of defects. Prior to this tool many of these defects could not detected until weeks or months later. Moving failure analysis to the FAB provides a means of complementing existing FAB inspection and defect review tools as well as providing independent, non-destructive electrical measurements at an early point in the manufacturing cycle [1] Once the wafer sites are non destructively AFP characterized, the wafer is returned to its front opening unified pod (FOUP) carrier and may be reintroduced into the manufacturing line without disruption for further inspection or processing. Whole wafer atomic force probe electrical characterization has been applied to 32nm, 28nm, 20nm and 14nm node technologies. In this paper we explore the cost benefits of performing non-destructive AFP measurements on whole wafers. We have found the methodology of employing a whole wafer AFP tool complements existing in-line manufacturing monitoring tools such as brightfield/dark field optical inspection, SEM in-line inspection and in-line E-beam voltage contrast inspection (EBI).


2021 ◽  
Vol 9 (1) ◽  
pp. 117-126
Author(s):  
Jonas Keukelier ◽  
Karl Opsomer ◽  
Thomas Nuytten ◽  
Stefanie Sergeant ◽  
Wouter Devulder ◽  
...  

Raman spectroscopy and electrical measurements are performed on sputtered GexSe1−x thin films to identify and link bond presence to electrical behaviour.


1997 ◽  
Vol 3 (S2) ◽  
pp. 1223-1224
Author(s):  
J. Liu ◽  
R. L. Ornberg ◽  
J. R. Ebner

Many industrial catalysts have a complex geometric structure to enable reacting gases or fluids to reach as much of the active surface of the catalyst as possible. The catalyzing surface frequently consists of a complex chemical mixture of different phases produced by an evolved chemical process. The active components are often very small particles dispersed on high-surface-area supports. The catalytic properties of this type of catalyst depend on the structure, composition, and morphology of the active species as well as the supports. TEM/STEM and associated techniques have been used extensively to characterize the structure and composition of supported catalysts. Surface morphology of supported catalysts is generally examined by secondary electron imaging, especially at low incident beam energies. It is, however, frequently found that small metal particles are not usually seen in SE images because of the complication of support topography


1999 ◽  
Vol 607 ◽  
Author(s):  
A. Saher Helmy ◽  
A.C. Bryce ◽  
C.N. Ironside ◽  
J.S. Aitchison ◽  
J.H. Marsh ◽  
...  

AbstractIn this paper we shall discuss techniques for accurate, non-destructive, optical characterisation of structures fabricated using quantum well intermixing (QWI). Spatially resolved photoluminescence and Raman spectroscopy were used to characterise the lateral bandgap profiles produced by impurity free vacancy disordering (IFVD) technology. Different features were used to examine the spatial resolution of the intermixing process. Features include 1:1 gratings as well as isolated stripes. From the measurements, the spatial selectivity of IFVD could be identified, and was found to be ∼4.5 μm, in contrast with the spatial resolution of the process of sputtering induced intermixing, which was found to be ∼2.5 μm. In addition, PL measurements on 1:1 gratings fabricated using IFVD show almost complete suppression of intermixing dielectric cap gratings with periods less than 10 microns. Finally, some insight into the limitations and merits of PL and Raman for the precision characterisation of QWI will be presented.


The Analyst ◽  
2022 ◽  
Author(s):  
Carol PY Lau ◽  
Wenao Ma ◽  
Kwan Yau Law ◽  
Maribel Lacambra ◽  
Kwok Chuen Wong ◽  
...  

Raman spectroscopy is a non-destructive analysis technique that provides detailed information about the chemical structure of the tumor. Raman spectra of 52 giant cell tumor of bone (GCTB), and 21...


2017 ◽  
Vol 14 (131) ◽  
pp. 20170174 ◽  
Author(s):  
Arno Germond ◽  
Vipin Kumar ◽  
Taro Ichimura ◽  
Jerome Moreau ◽  
Chikara Furusawa ◽  
...  

Scientists are always on the lookout for new modalities of information which could reveal new biological features that are useful for deciphering the complexity of biological systems. Here, we introduce Raman spectroscopy as a prime candidate for ecology and evolution. To encourage the integration of this microscopy technique in the field of ecology and evolution, it is crucial to discuss first how Raman spectroscopy fits within the conceptual, technical and pragmatic considerations of ecology and evolution. In this paper, we show that the spectral information holds reliable indicators of intra- and interspecies variations, which can be related to the environment, selective pressures and fitness. Moreover, we show how the technical and pragmatic aspects of this modality (non-destructive, non-labelling, speed, relative low cost, etc.) enable it to be combined with more conventional methodologies. With this paper, we hope to open new avenues of research and extend the scope of available methodologies used in ecology and evolution.


2004 ◽  
Vol 3 (2) ◽  
pp. 165-174 ◽  
Author(s):  
S.E. Jorge Villar ◽  
H.G.M. Edwards

The special characteristics of Raman spectroscopy (relative insensitivity to water, non-destructive detection, sensitivity to bio- and geosignatures, molecular structural composition information, etc.) together with the development of miniaturized Raman spectrometers make the consideration of this technique for future robotic landers on planetary surfaces, particularly Mars, a very interesting option. The development of light and rugged Raman spectrometers limits the possible scope of the instrumentation which has particular importance in the recognition of biomolecular and mineral signatures. In this work, we evaluate the spectral resolution and scan time parameters and the effect that they have on the Raman spectra of extremophilic biomolecules, together with the wavenumber ranges which are critical for the detection of life signals. This is of vital relevance for the design of miniaturized Raman spectrometer systems. From our results, we conclude that for extraterrestrial biological signatures unambiguous Raman spectral identification provided with a minimum of 16 cm−1 spectral resolution is required for the most significant biosignature wavenumber range in the 1700–700 cm−1 region.


2017 ◽  
Vol 53 (16) ◽  
pp. 2451-2454 ◽  
Author(s):  
Naresh Kumar ◽  
Marek M. Drozdz ◽  
Haibo Jiang ◽  
Daniela M. Santos ◽  
David J. Vaux

Non-destructive & label-free nanoscale mapping of newly-synthesised phospholipid molecules inside a biological cell is demonstrated using tip-enhanced Raman spectroscopy for the first time.


Geophysics ◽  
2006 ◽  
Vol 71 (2) ◽  
pp. H13-H24 ◽  
Author(s):  
Gamal Z. Abdel Aal ◽  
Lee D. Slater ◽  
Estella A. Atekwana

To investigate the potential role that indigenous microorganisms and microbial processes may play in altering lowfrequency electrical properties, induced-polarization (IP) measurements in the frequency range of 0.1 to 1000 Hz were acquired from sediment samples retrieved from a site contaminated by hydrocarbon undergoing intrinsic biodegradation. Increased imaginary conductivity and phase were observed for samples from the smear zone (contaminated with residual-phase hydrocarbon), exceeding values obtained for samples contaminated with dissolved-phase hydrocarbons, and in turn, exceeding values obtained for uncontaminated samples. Real conductivity, although generally elevated for samples from the smear zone, did not show a strong correlation with contamination. Controlled experiments on uncontaminated samples from the field site indicate that variations in surface area, electrolytic conductivity, and water content across the site cannot account for the high imaginary conductivity observed within the smear zone. We suggest that microbial processes may be responsible for the enhanced IP response observed at contaminated locations. Scanning electron microscopy and IP measurements during acid leaching indicate that etched pits on mineral surfaces — caused by the production of organic acids or formed during microbial colonization of these surfaces — are not the cause of the IP enhancement. Rather, we postulate that the accumulation of microbial cells (biofilms) with high surface area at the mineral-electrolyte interface generates the IP response. These findings illustrate the potential use of electrical measurements to noninvasively monitor microbial activity at sites undergoing natural hydrocarbon degradation.


Sign in / Sign up

Export Citation Format

Share Document