Electrical Defect Analysis Following Pulsed Laserirradiation of Unimplanted GaAs

1982 ◽  
Vol 13 ◽  
Author(s):  
D. Pribat ◽  
S. Delage ◽  
D. Dieumegard ◽  
M. Croset ◽  
P.C. Srivastava ◽  
...  
Keyword(s):  
Energy Density ◽  
Laser Irradiation ◽  
Laser Energy ◽  
Subsurface Layer ◽  
Defect Analysis ◽  
Current Voltage ◽  
Capacitance Voltage ◽  
Important Barrier ◽  
Induced Defects ◽  
Pulsed Laser Irradiation

ABSTRACTCurrent-voltage, capacitance-voltage and defect spectroscopy techniques are used to characterize the electrical properties of GaAs crystals after pulsed laser irradiation with either a Nd-YAG or a Ruby laser. I(V) and C(V) measurements performed in conjunction on Au/GaAs Schottky structures after laser irradiation at low energy density show an important barrier lowering, of the order of 300mV. Carrier compensation up to 6×lO16/cm3 is observed in a subsurface layer whose thickness increases with deposited laser energy density. D.L.T.S. is used to study the tail of laser induced defects behind the heavily compensated layer. Finally the results are compared to those obtained following conventional thermal treatment.

Er-Doping in Silicon by Pulsed Laser Irradiation

1993 ◽  
Vol 301 ◽  
Author(s):  
Kenshiro Nakashima
Keyword(s):  
Energy Density ◽  
Laser Irradiation ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Laser Energy Density ◽  
Er Doping ◽  
Erbium Ions ◽  
State Regime ◽  
Er Doped ◽  
Pulsed Laser Irradiation

ABSTRACTErbium ions were successfully doped in silicon by pulsed laser irradiation above the threshold laser energy density. Photoluminescence peaks at 1.54, 1.59 and 1.64 µm from Er-optical centers were observed after annealing of Er-doped samples. The intensity of the 1.54 µm Er-emission band increased upon increase in the laser energy density, and then gradually decreased after reaching the maximum, due to the laser sputtering of the silicon substrate. Oxygen atoms, which were unintentionally codoped with Er-ions, were found to be distributed in the same region as in Er-ions, and were suggested to play roles to activate Er-optical centers. The maximum concentration of Er-ions doped in the solid state regime were estimated to be the order of 1018 cm−3 by the Rutherford backscattering measurements.

Doping of GaAs From Silane Decomposition Under Pulsed Laser Irradiation

1983 ◽  
Vol 29 ◽  
Author(s):  
D. Pribat ◽  
D. Dieumegard ◽  
B. Dessertenne ◽  
J. Chaplart
Keyword(s):  
High Pressure ◽  
Energy Density ◽  
Laser Irradiation ◽  
Sheet Resistance ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Compensation Mechanism ◽  
Yag Laser ◽  
Oxygen Penetration ◽  
Pulsed Laser Irradiation

ABSTRACTWe have studied silicon incorporation in GaAs subsequent to Nd-YAG laser irradiation through high pressure silane atmospheres. The process involves SiH4 pyrolysis at contact with a laser-melted GaAs surface, and incorporation of the released Si atoms in the melt. SIMS analyses have allowed us to study silicon incorporation as a function of SiH4 pressure, laser energy density and number of laser shots. The high sheet resistance of the doped layers indicates that the silicon atoms are poorly electrically activated. A compensation mechanism is discussed based on oxygen penetration from native GaAs oxide layers.

Formation of polytype microstructure in pulsed-laser-irradiated sapphire substrates

1995 ◽  
Vol 53 ◽  
pp. 344-345
Author(s):  
Siqi Cao ◽  
A. J. Pedraza ◽  
L. F. Allard ◽  
D. H. Lowndes
Keyword(s):  
Energy Density ◽  
Laser Irradiation ◽  
Electroless Deposition ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Surface Modifications ◽  
Near Surface ◽  
Sapphire Substrates ◽  
Hcp Structure ◽  
Pulsed Laser Irradiation

Surface modifications of wide-gap materials are produced by pulsed laser irradiation. Under given conditions, these near-surface modifications can promote adhesion enhancement of deposited thin film materials, and activation for electroless deposition. AIN decomposes during laser irradiation leaving a metallic film on the surface. High density dislocations were observed in the surface layer of AIN that was laser melted but not decomposed. The laser melted alumina becomes amorphous at a laser energy density of ~1J/cm2. In sapphire, γ-alumina is formed when the sample is laser irradiated in Ar/4%H2. Here, we report the formation of a new structure in laser-irradiated sapphire.Optically polished c-axis sapphire substrates were laser-irradiated in an Ar/4%H2 atmosphere at 4J/cm2 energy density, using a 308 nm-wavelength laser with a pulse duration of ~40 ns. Sapphire (A12O3) has a space group R 3 c and can be described as an hcp structure having oxygen and aluminum layers alternately stacking along the c-axis.

Copper ohmic contacts to n-type SiC formed with pulsed excimer laser irradiation

2001 ◽  
Vol 680 ◽  
Author(s):  
K. Abe ◽  
M. Sumitomo ◽  
O. Eryu ◽  
K. Nakashima
Keyword(s):  
Energy Density ◽  
Laser Irradiation ◽  
Excimer Laser ◽  
Ohmic Contacts ◽  
Laser Energy ◽  
Contact Layer ◽  
Ohmic Behavior ◽  
Current Voltage ◽  
Excimer Laser Irradiation ◽  
Current Voltage Characteristics

ABSTRACTCopper-based ohmic contacts to n-type 6H-SiC have been investigated. In this study, ohmic contacts have been fabricated with pulsed excimer laser irradiation to Cu-deposited substrates at room temperature. It is shown that current-voltage characteristics depend on the laser energy density. Contacts formed by the laser irradiation at the energy density above 1.2 J/cm2 have shown the ohmic behavior. Cu atoms have slightly diffused into SiC by the laser irradiation at 1.4 J/cm2. As a result, a thin ohmic contact layer has been obtained by the laser processing. AES and XRD study have revealed that a Cu-SiC alloy containing Cu silicide (Cu3Si) is formed by the laser irradiation.

Electrical Properties of Solid Phase Crystallized Silicon Films

2001 ◽  
Vol 664 ◽  
Author(s):  
Tadashi Watanabe ◽  
Hajime Watakabe ◽  
Toshiyuki Sameshima
Keyword(s):  
Heat Treatment ◽  
Electrical Conductivity ◽  
Energy Density ◽  
Laser Irradiation ◽  
Carrier Mobility ◽  
Crystalline Silicon ◽  
Solid Phase ◽  
Laser Energy ◽  
Silicon Films ◽  
Laser Energy Density

ABSTRACTIn this study, the carrier mobility and density for solid phase crystallized (SPC) silicon films fabricated at 600 °C for 48 hours are analyzed by free carrier optical absorption. The carrier mobility is 40 cm2/Vs for SPC films doped with 6×1019-cm−3-phosphorus atoms. This analysis suggests the SPC films have fine crystalline grains closed to single crystalline silicon. In addition, initial carrier density was 3×1019 cm−3, which increased to 6×1019 cm−3by XeCl excimer laser irradiation of 500mJ/cm2. The inactivated regions in SPC films are reduced by laser irradiation. However, the electrical conductivity after laser irradiation for SPC films doped with 6×1018-cm−3-phosphorus atoms decreased from 3.3 to 0.018 S/cm as laser energy density increased to 500mJ/cm2. On the other hand, the electrical conductivity increased from 14.7 to 31.3 S/cm with similar increase of laser energy density after H2O vapor heat treatment at 260°C for 3 hours with 1.3 MPa. Furthermore, the characteristics of n-channel TFTs fabricated with initial SPC films as well as SPC films which was irradiated by laser at 425mJ/cm2 are also researched. The threshold voltage is decreased from 3.8 to 2.0 V by laser irradiation. Threshold voltages of both cases are decreased from 3.8 to 2.4 V for no-laser irradiation and from 2.0 to 0.8 V for laser irradiation, after H2O vapor heat treatment at 310°C for 1 hour with 9.0MPa. Based on the above trial, the defect reduction method combining laser irradiation and H2O vapor heat treatment has proved to be very effective for SPC films and SPC TFTs.

Low-Energy, Pulsed-Laser Irradiation of Amorphous Silicon: Melting and Resolidification at Two Fronts

1984 ◽  
Vol 35 ◽  
Author(s):  
W. Sinke ◽  
F.W. Saris
Keyword(s):  
Amorphous Silicon ◽  
Laser Irradiation ◽  
Surface Segregation ◽  
Crystalline Silicon ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Surface Region ◽  
Low Energy ◽  
Double Peak Structure ◽  
Pulsed Laser Irradiation

ABSTRACTAfter low-energy pulsed-laser irradiation of Cu-implanted silicon, a double-peak structure is observed in the Cu concentration profile, which results from the occurrence of two melts. From Cu surface segregation we calculate the depth of the surface melt. Cu segregation near the position of the amorphous-crystalline interface gives evidence for a self-propagating melt, moving from the surface region towards the crystalline substrate. Measurements of As-redistribution and of sheet resistance as a function of laser energy density in As-implanted silicon are consistent with the crystallization model which is derived from the effects as observed in Cu-implanted silicon.The results imply a large difference in melting temperature, heat conductivity and heat of melting between amorphous silicon and crystalline silicon.

Processing Grinding-Damaged Silicon Wafers by High-Frequency Nano-Second Laser Irradiation

2009 ◽  
Vol 76-78 ◽  
pp. 451-456
Author(s):  
Ji Wang Yan ◽  
Sei Ya Muto ◽  
Tsunemoto Kuriyagawa
Keyword(s):  
Energy Density ◽  
Amorphous Silicon ◽  
Laser Irradiation ◽  
High Frequency ◽  
Laser Energy ◽  
Large Diameter ◽  
Silicon Wafers ◽  
Density Level ◽  
Transmission Electron ◽  
Beam Center

Ultraprecision diamond-ground silicon wafers were irradiated by a high-frequency nanosecond pulsed Nd:YAG laser equipped on a four-axis numerically controlled stage. The resulting specimens were characterized using a white-light interferometer, a micro-Raman spectroscope and a transmission electron microscope. The results indicate that around the laser beam center where the laser energy density is sufficiently high, the grinding-induced amorphous silicon was completely transformed into the single-crystal structure. The optimum conditions for one- and two-dimensional overlapping irradiation were experimentally obtained for processing large-diameter silicon wafers. It was found that the energy density level required for completely removing the dislocations is higher than that for recrystallizing the amorphous silicon. After laser irradiation, the surface unevenness has been remarkably flattened.

Yield Analysis Based on the Defect Analysis with Derivative Method

2015 ◽  
Vol 781 ◽  
pp. 160-163 ◽  
Author(s):  
Warakorn Praepattharapisut ◽  
Weera Pengchan ◽  
Toempong Phetchakul ◽  
Amporn Poyai
Keyword(s):  
Silicon Wafer ◽  
Calculated Data ◽  
Cmos Technology ◽  
Defect Analysis ◽  
Yield Analysis ◽  
Current Voltage ◽  
Capacitance Voltage ◽  
Derivative Method ◽  
Actual Yield ◽  
Characteristic Measurement

This paper presented the corresponding between the yield equation prediction from Poisson, Murphy with wafer actual yield on the silicon wafer with 0.8 μm CMOS technology. The defect analysis with derivative method, current - voltage and capacitance-voltage of diode characteristic measurement, is used to define the defect in p-n junction on silicon wafer. The different sampling numbers of chips are used to calculate the yield. Finally the calculated data and actual would be compared and found that at sampling number is 25, the tolerance from actual yield is less than 3%.

Electronic Levels Induced by Irradiation in 4H-Silicon Carbide

2005 ◽  
Vol 483-485 ◽  
pp. 359-364 ◽  
Author(s):  
Antonio Castaldini ◽  
Anna Cavallini ◽  
L. Rigutti ◽  
Filippo Nava
Keyword(s):  
Silicon Carbide ◽  
Deep Level ◽  
Particle Energy ◽  
Free Carrier ◽  
Current Voltage ◽  
Capacitance Voltage ◽  
Current Voltage Characteristics ◽  
Transient Spectroscopy ◽  
Induced Defects ◽  
Irradiation Induced Defects

The effects of irradiation with protons and electrons on 4H-silicon carbide epilayers were investigated. The particle energy was 6.5 and 8.2 MeV. The electronic levels associated with the irradiation-induced defects were analyzed by current-voltage characteristics and deep level transient spectroscopy measurements up to 700 K. In the same temperature range the apparent free carrier concentration was measured by capacitance-voltage characteristics to monitor possible compensation effects due to the deep level associated to the induced defects. Introduction rate, enthalpy and capture cross-section of such deep levels were compared and some conclusions about the nature of the defects were drawn.

Raman Measurements on Graphite Modified by High Power Laser Irradiation

1984 ◽  
Vol 35 ◽  
Author(s):  
J. Steinbeck ◽  
G. Braunstein ◽  
M.S. Dresselhaus ◽  
B.S. Elman ◽  
T. Venkatesan
Keyword(s):  
Energy Density ◽  
Laser Pulse ◽  
Laser Irradiation ◽  
High Power ◽  
Laser Energy ◽  
Laser Pulses ◽  
Laser Energy Density ◽  
High Power Laser ◽  
Power Laser ◽  
Raman Microprobe

AbstractThe behavior of highly anisotropic materials under short pulses of high power laser irradiation has been studied by irradiating highly oriented pyrolytic graphite (HOPG) with 30 nsec Ruby-laser pulses with energy densities between 0.1 and 5.0J/cm2. Raman spectroscopy has been used to investigate the laser-induced modifications to the crystalline structure as a function of laser energy density of the laser pulse. A Raman microprobe was used to investigate the spatial variations of these near-surface regions. The irradiation of HOPG with energy densities above ~ 0.6J/cm2 leads to the appearance of the ~ 1360 cm-1 disorder-induced line in the first order Raman spectrum. The intensity of the ~ 1360cm-1 line increases with increasing laser energy density. As the energy density of the laser pulse reaches about 1.0J/cm2, the ~ 1360cm-1 line and the ~ 1580cm-1 Raman-allowed mode broaden and coalesce into a broad asymmetric band, indicating the formation of a highly disordered region, consistent with RBS-channeling measurements. However, as the laser energy density of the laser pulses is further increased above 3.0J/cm2, the two Raman lines narrow and can again be resolved suggesting laser-induced crystallization. The Raman results are consistent with high resolution electron microscopy observations showing the formation of randomly oriented crystallites. Raman Microprobe spectra revealed three separate regions of behavior: (i) an outer unirradiated region where the material appears HOPG-like with a thin layer of material coating the surface, (ii) an inner irradiated region where the structure is uniform, but disordered, and (iii) an intermediate region between the other regions where the structure is highly disordered. The changes in structure of the inner region are consistent with the behavior observed with RBS and conventional Raman spectra. The identification of an amorphous carbon-like layer on the outer region is consistent with a large thermomechanical stress at the graphite surface, introduced by the high power laser pulse, and known to occur in metals.

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