Rapid Heating of Ion-Implanted Silicon by High-Power Pulsed Microwave Radiation

1988 ◽  
Vol 124 ◽  
Author(s):  
R. B. James ◽  
P. R. Bolton ◽  
R. A. Alvarez ◽  
W. H. Christie
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Light Emission ◽  
Electrical Breakdown ◽  
Rapid Heating ◽  
Surface Region ◽  
Time Resolved ◽  
Near Surface ◽  
Microwave Induced Plasma ◽  
Spatially Homogeneous ◽  
Secondary Ion

ABSTRACTWe have used 1.1-μs microwave pulses at a frequency of 2.856 GHz to rapidly heat the near-surface region of arsenic-implanted silicon. The samples were irradiated inside a WR-284 waveguide by single-pass TE10 traveling wave pulses. Post-irradiation studies show that surface melting occurs for incident pulse powers exceeding about 3 MW. Time-resolved measurements of the microwave reflectivity (R) show that there is an abrupt and large increase in R for microwave pulse powers greater than the melt threshold. Significant light emission was also observed from the test cell, which is most likely due to the relaxation of a microwave-induced plasma formed by electrical breakdown of gas. Using secondary ion mass spectrometry, we measured the depth profile of the implanted arsenic and found that the penetration of the melt front in the near-surface region is not spatially homogeneous over the silicon surface.

Time-Resolved and Post-Irradiation Studies of the Interaction of High-Power Pulsed Microwave Radiation with Silicon

1986 ◽  
Vol 74 ◽  
Author(s):  
R. B. James ◽  
P. R. Bolton ◽  
R. A. Alvarez ◽  
R. E. Valiga ◽  
W. H. Christie
Keyword(s):  
Mass Spectrometry ◽  
Secondary Ion Mass Spectrometry ◽  
Surface Region ◽  
Surface Damage ◽  
Threshold Value ◽  
Optical Measurements ◽  
Time Resolved ◽  
Near Surface ◽  
Reflected Power ◽  
Secondary Ion

AbstractWe have measured the microwave-induced damage to the near-surface region of silicon for 1.9-μs pulses at a frequency of 2.856 GHz and a pulse power of up to 7.2 MW. Rectangular samples were irradiated in a test section of WR-284 waveguide that was filled with freon to a pressure of 30 psig. Incident, transmitted and reflected powers were monitored with directional couplers and fast diodes. The results of the time-resolved optical measurements show that the onset of surface damage is accompanied by a large increase in the reflected power. Examination of the irradiated surfaces shows that the degree of damage is greatest near the edges of the samples. Using secondary ion mass spectrometry to profile the implanted As, we find that the microwave pulses can melt the near-surface region of the material for pulse powers exceeding a threshold value.

Pulsed Microwave Irradiation of Graphite/Epoxy Composites

1988 ◽  
Vol 124 ◽  
Author(s):  
R. B. James ◽  
P. R. Bolton ◽  
R. A. Alvarez
Keyword(s):  
Light Emission ◽  
Electrical Breakdown ◽  
Surface Region ◽  
Surface Damage ◽  
Sample Surface ◽  
Optical Measurements ◽  
Time Resolved ◽  
Near Surface ◽  
Reflected Power ◽  
Surface Decomposition

ABSTRACTWe have measured the microwave-induced damage to the near-surface region of a graphite/epoxy composite material for 1.1-μs pulses at a frequency of 2.856 GHz and a pulse power of up to 8 MW. Rectangular samples were irradiated by single-pass TE10 traveling wave pulses inside a WR-284 waveguide, and in situ and post irradiation studies were performed to characterize the material modifications induced by the microwave pulses. The results of the time-resolved optical measurements in vacuo show that surface decomposition of the epoxy resin occurs for incident pulse powers exceeding 1.1 MW, and that the surface damage is accompanied by a large increase in the reflected microwave power. Simultaneous with the onset of surface decomposition, significant light emission from the sample and a large enhancement of the gas pressure in the test cell were observed. The large increments in both the reflected power and light emission are attributed to the formation of a plasma due to electrical breakdown of the gas at (or near) the sample surface.

Deposition of Low-Stress Encapsulants on InP and GaAs

1986 ◽  
Vol 75 ◽  
Author(s):  
U. K. Chakrabarti ◽  
S. J. Pearton ◽  
H. Barz ◽  
A. R. Vonneida ◽  
K. T. Short ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Secondary Ion Mass Spectrometry ◽  
Surface Region ◽  
Near Surface ◽  
Deposition Parameters ◽  
Direct Measurements ◽  
Dopant Redistribution ◽  
Doped Glass ◽  
Phosphorus Doped ◽  
Secondary Ion

AbstractAℓN deposited by D.C. triode sputtering and spin-on, phosphorus-doped glass (PSG) layers on GaAs and InP were investigated as encapsulants. These films have similar expansion coefficients to both GaAs and InP, minimizing the amount of strain induced in the near-surface region of the underlying wafer. We have quantified this effect by direct measurements of the stress in the films and by using secondary ion mass spectrometry profiling to measure the redistribution of Cr and Fe in encapsulated GaAs and InP respectively during high temperature processing. The dopant redistribution is considerably less for the AℓN and PSG films compared to the more conventional SiO2 and Si3N4 layers. The interaction of the films with the substrate at elevated temperatures is minimal as determined by Auger profiling and the electrical properties of the surface after removal of the encapsulants. The composition of the films remains essentially constant after annealing, as measured by Rutherford backscattering, and the thickness uniformity over large wafer diameters (2″) can be excellent with close control of the deposition parameters. The activation characteristics of low dose, Si-implanted layers in GaAs using either PSG or AℓN are comparable to those obtained using capless annealing or SiO2 or Si3N4 encapsulation.

Correction Method for Ion Yield Transients in the Near Surface Region of Sims Depth Profiles

1985 ◽  
Vol 54 ◽  
Author(s):  
S. R. Bryan ◽  
R. W. Linton ◽  
D. P. Griffis
Keyword(s):  
Steady State ◽  
Secondary Ion Mass Spectrometry ◽  
High Sensitivity ◽  
Depth Resolution ◽  
Surface Region ◽  
Correction Method ◽  
Ion Concentration ◽  
Near Surface ◽  
Ion Yields ◽  
Secondary Ion

As solid state device features continue to decrease in size, it has become more important to characterize dopant concentrations within the first several hundred angstroms of the surface. Secondary ion mass spectrometry (SIMS) is the technique of choice for dopant depth profiling due to its high sensitivity and good depth resolution. In order to increase the sensitivity of SIMS, electropositive elements (e.g. oxygen) or electronegative elements (e.g. cesium) are used as primary ion species to enhance positive or negative secondary ion yields, respectively. This has the disadvantage, however, of causing secondary ion yields to vary by up to several orders of magnitude over the first few hundred angstroms of a depth profile as the implanted primary ion concentration increases [1,2]. Secondary ion yields stabilize once the primary ion reaches a steady state concentration, which occurs at a depth proportional to the range of the primary ions in the solid. This ion yield transient artifact hinders quantification of dopant concentrations until the primary ion concentration reaches steady state.

Development of Novel Photoelectrode Materials with Improved Charge Separation Properties

2014 ◽  
Vol 975 ◽  
pp. 224-229 ◽  
Author(s):  
Leigh Russell Sheppard ◽  
Marta Bello Lamo ◽  
Thomas Dittrich ◽  
Richard Wuhrer
Keyword(s):  
Photoelectron Spectroscopy ◽  
Charge Separation ◽  
Secondary Ion Mass Spectrometry ◽  
Surface Region ◽  
Charge Carriers ◽  
Near Surface ◽  
Surface Photovoltage Spectroscopy ◽  
Related Defect ◽  
Compositional Gradients ◽  
Secondary Ion

This investigation was aimed at identifing the scope for exploiting segregation phenomena to improve the ability of doped TiO2 to separate photo-generated charge carriers. By applying several controlled conditions of temperature and oxygen activity during the annealing of Nb-doped TiO2 (0.65 at. %), compositional gradients were imposed within the surface and near-surface regions due to solute segregation. These compositional gradients were characterised using secondary ion mass spectrometry (SIMS) and Xray photoelectron spectroscopy (XPS), and then tested for charge separation abilities using surface photovoltage spectroscopy (SPS). This investigation has revealed that processing Nb-doped TiO2 under conditions that favour the depletion of Nb from the surface and near-surface region yields stronger charge separation. While this is attributed to the formation of a homo-junction that is providing additional driving force for charge separation, the altered impact of Nb5+ and related defect disorder may also play a role. This investigation has provided encouraging preliminary outcomes to stimulate further investigations.

Surface Analysis Of Lcd Materials iN Various Stages of Production by Time-of-Flight Secondary Ion Mass Spectroscopy (TOF-SIMS)

1994 ◽  
Vol 345 ◽  
Author(s):  
J.J. Lee ◽  
P.M. Lindley ◽  
R.W. Odom
Keyword(s):  
Mass Spectrometry ◽  
Surface Analysis ◽  
Secondary Ion Mass Spectrometry ◽  
Time Of Flight ◽  
Surface Region ◽  
Near Surface ◽  
Tof Sims ◽  
Analysis Technique ◽  
Spectrometry Technique ◽  
Secondary Ion

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is a surface analysis technique which provides a sensitive characterization of the elemental and molecular composition of the near-surface region (top few monolayers) of solid materials1. This mass spectrometry technique can also localize the distribution of specific elements, molecules or molecular fragments at submicrometer (µm) lateral resolutions.2

Study of Layer Disordering in MeV Si Implanted GaAs/AlGaAs Superlattices.

1988 ◽  
Vol 144 ◽  
Author(s):  
Samuel Chen ◽  
S.-Tong Lee ◽  
G. Braunstein ◽  
G. Rajeswaran
Keyword(s):  
Molecular Beam ◽  
Secondary Ion Mass Spectrometry ◽  
Surface Region ◽  
Defect Band ◽  
Implantation Energy ◽  
Near Surface ◽  
Free Zone ◽  
Annealing Conditions ◽  
Transmission Electron ◽  
Secondary Ion

ABSTRACTLayer intermixing in MeV Si-implanted quantum well superlattices (SLs) has been studied by transmission electron microscopy, secondary ion mass spectrometry and Rutherford backscattering spectroscopy. Molecular beam epitaxially grown GaAs(200Å) - Al0. 5Ga0.5As(200Å) SLs were implanted with 1 MeV Si+ at doses between 3 × 1014 and 1 × 1016/cm2. The implanted SLs were either furnace annealed at 850°C for 3 hr or rapid thermally annealed at 1050°C for 10 sec, both under GaAs proximity capping conditions. Totally mixed regions were observed only for the SLs implanted with 1 × 1016 Si/cm2 and then furnace annealed at 850°C for 3 hr. For the same dose, the RTA annealed SLs only showed slight layer intermixing. At lower doses, no appreciable intermixing was detected in either furnace or RTA annealed samples. By contrast, under either annealing condition extensive intermixing has been demonstrated for lower energy (220 keV) implantation, but at doses almost two orders of magnitude lowerl XTEM showed that in all the annealed samples, a defect-free zone existed in the near-surface region, followed by a band of secondary defects, with the maximum density located at about 1 μm below the surface. In the disordered samples, the position of the intermixed layers correlated with the defect band maximum. Under both annealing conditions, Si concentration profiles only showed slight broadening, and they correlated with the distribution of secondary defects as well as with the depth of the intermixed layers. The effects of dynamic annealing and surface on the implantation energy dependence, i.e., MeV vs. keV, of layer intermixing are discussed.

Near-Surface Aggregation of Sn In Heavily Sn-Doped GaAs Films Grown By Molecular Beam Epitaxy

1985 ◽  
Vol 43 ◽  
pp. 368-369
Author(s):  
S. H. Chen
Keyword(s):  
Molecular Beam Epitaxy ◽  
Cross Section ◽  
Electron Spectroscopy ◽  
Molecular Beam ◽  
Surface Segregation ◽  
Secondary Ion Mass Spectrometry ◽  
Specimen Preparation ◽  
Near Surface ◽  
Gaas Films ◽  
Secondary Ion

Sn has been used extensively as an n-type dopant in GaAs grown by molecular-beam epitaxy (MBE). The surface accumulation of Sn during the growth of Sn-doped GaAs has been observed by several investigators. It is still not clear whether the accumulation of Sn is a kinetically hindered process, as proposed first by Wood and Joyce, or surface segregation due to thermodynamic factors. The proposed donor-incorporation mechanisms were based on experimental results from such techniques as secondary ion mass spectrometry, Auger electron spectroscopy, and C-V measurements. In the present study, electron microscopy was used in combination with cross-section specimen preparation. The information on the morphology and microstructure of the surface accumulation can be obtained in a fine scale and may confirm several suggestions from indirect experimental evidence in the previous studies.

Time-Resolved Reflectivity Measurements of Silicon And Germanium Using A Pulsed Excimer Laser

1985 ◽  
Vol 51 ◽  
Author(s):  
G. E. Jellison ◽  
D. H. Lowndes ◽  
D. N. Mashburn ◽  
R. F. Wood
Keyword(s):  
Excimer Laser ◽  
Surface Region ◽  
Finite Energy ◽  
Time Resolved ◽  
Model Calculations ◽  
Near Surface ◽  
Maximum Reflectivity ◽  
Liquid Phases ◽  
Silicon And Germanium ◽  
Melt Duration

ABSTRACTTime-resolved reflectivity measurements of silicon and germanium have been made during pulsed KrF excimer laser irradiation. The reflectivity was measured simultaneously at both 1152 and 632.8 nm wavelengths, and the energy density of each laser pulse was monitored. The melt duration and the time of the onset of melting were measured and compared with the results of melting model calculations. For energy densities just above the melting threshold, it was found that the melt duration was never less than 20 ns for Si and 25 ns for Ge, while the maximum reflectivity increased from the value of the hot solid to that of the liquid over a finite energy range. These results, along with a reinterpretation of earlier time-resolved ellipsometry measurements, indicate that, during the melt-in process, the near-surface region does not melt homogeneously, but rather consists of a mixture of solid and liquid phases. The reflectivity at the onset of melting and in the liquid phase have been measured at both 632.8 and 1152 nm, and are compared with the results found in the literature.

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