Formation of Shallow P+ Junctions Using Two-Step Anneals

1984 ◽  
Vol 35 ◽  
Author(s):  
C.I. Drowley ◽  
J. Adkisson ◽  
D. Peters ◽  
S.-Y. Chiang
Keyword(s):  
Amorphous Silicon ◽  
Silicon Layer ◽  
Amorphous Layer ◽  
Single Step ◽  
Step Process ◽  
Enhanced Diffusion ◽  
Isothermal Anneal

ABSTRACTShallow (0.15-0.2 μm deep) p+ junctions have been formed using boron implanted into silicon which was pre-amorphized using a silicon implant. The implants were annealed using a two-step process; initially the wafers were furnace annealed at 600 °C for 100 min., followed by a rapid isothermal anneal (RIA) at 950-1100 °C for 10 sec. For comparison, some wafers were only given a single-step rapid isothermal anneal at 950-1100 °C for 10 sec. The shallowest junctions were formed when the amorphous silicon layer was deeper than the boron implant, because of the suppression of channelling. When the amorphous/crystalline interface was shallower than the tail of the boron implant, some channeling occurred. This channeling tail exhibited an enhanced diffusion during the single-step RIA which was reduced significantly by the two-step anneal. When the amorphous layer was deeper than the boron implant, the single-step and two-step anneals gave identical results.

Effect of Fluorine on the Diffusion of Boron in Amorphous Silicon

2002 ◽  
Vol 717 ◽  
Author(s):  
J. M. Jacques ◽  
L. S. Robertson ◽  
K. S. Jones ◽  
Joe Bennett
Keyword(s):  
Amorphous Silicon ◽  
Boron Concentration ◽  
Solid Phase ◽  
Amorphous Layer ◽  
Boron Diffusion ◽  
Enhanced Diffusion ◽  
Diffusion Characteristics ◽  
Junction Formation ◽  
Amorphous Surface ◽  
Boron Diffusivity

AbstractFluorine and boron co-implantation within amorphous silicon has been studied in order to meet the process challenges regarding p+ ultra-shallow junction formation. Previous experiments have shown that fluorine can reduce boron TED (Transient Enhanced Diffusion), enhance boron solubility and reduce sheet resistance. In this study, boron diffusion characteristics prior to solid phase epitaxial regrowth (SPER) of the amorphous layer in the presence of fluorine are addressed. Samples were pre-amorphized with Si+ at a dose of 1x1015 ions/cm2 and energy of 70 keV, leading to a deep continuous amorphous surface of approximately 1500 Å. After pre-amorphization, B+ was implanted at a dose of 1x1015 ions/cm2 and energy of 500 eV, while F+ was implanted at a dose of 2x1015 ions/cm2 and energies ranging from 3 keV to 9 keV. Subsequent furnace anneals for the F+ implant energy of 6 keV were conducted at 550°C, for times ranging from 5 minutes to 260 minutes. During annealing, the boron in samples co-implanted with fluorine exhibited significant enhanced diffusion within amorphous silicon. After recrystallization, the boron diffusivity was dramatically reduced. Boron in samples with no fluorine did not diffuse during SPER. Prior to annealing, SIMS profiles demonstrated that boron concentration tails broadened with increasing fluorine implant energy. Enhanced dopant motion in as-implanted samples is presumably attributed to implant knock-on or recoil effects.

Enhanced Boron Diffusion in Amorphous Silicon

2004 ◽  
Vol 810 ◽  
Author(s):  
J.M. Jacques ◽  
N. Burbure ◽  
K.S. Jones ◽  
M.E. Law ◽  
L.S. Robertson ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Room Temperature ◽  
Solid Phase ◽  
Amorphous Layer ◽  
Boron Diffusion ◽  
Cross Sectional ◽  
Enhanced Diffusion ◽  
Transmission Electron ◽  
Variable Angle Spectroscopic Ellipsometry ◽  
Secondary Ion

ABSTRACTIn prior works, we demonstrated the phenomenon of fluorine-enhanced boron diffusion within self-amorphized silicon. Present studies address the process dependencies of low temperature boron motion within ion implanted materials utilizing a germanium amorphization. Silicon wafers were preamorphized with either 60 keV or 80 keV Ge+ at a dose of 1×1015 atoms/cm2. Subsequent 500 eV, 1×1015 atoms/cm211B+ implants, as well as 6 keV F+ implants with doses ranging from 1×1014 atoms/cm2 to 5×1015 atoms/cm2 were also done. Furnace anneals were conducted at 550°C for 10 minutes under an inert N2 ambient. Secondary Ion Mass Spectroscopy (SIMS) was utilized to characterize the occurrence of boron diffusion within amorphous silicon at room temperature, as well as during the Solid Phase Epitaxial Regrowth (SPER) process. Amorphous layer depths were verified through Cross-Sectional Transmission Electron Microscopy (XTEM) and Variable Angle Spectroscopic Ellipsometry (VASE). Boron motion within as-implanted samples is observed at fluorine concentrations greater than 1×1020 atoms/cm3. The magnitude of the boron motion scales with increasing fluorine dose and concentration. During the initial stages of SPER, boron was observed to diffuse irrespective of the co-implanted fluorine dose. Fluorine enhanced diffusion at room temperature does not appear to follow the same process as the enhanced diffusion observed during the regrowth process.

Complete Suppression of the Transient Enhanced Diffusion of B Implanted in Preamorphized Si by Interstitial Trapping in a Spatially Separated C-Rich Layer

2002 ◽  
Vol 717 ◽  
Author(s):  
E. Napolitani ◽  
A. Coati ◽  
D. De Salvador ◽  
A. Carnera ◽  
S. Mirabella ◽  
...  
Keyword(s):  
Silicon Layer ◽  
Complementary Metal Oxide Semiconductor ◽  
Amorphous Layer ◽  
Oxide Semiconductor ◽  
Complete Suppression ◽  
Silicon Sample ◽  
Enhanced Diffusion ◽  
Transient Enhanced Diffusion ◽  
Ultra Shallow Junctions ◽  
Technology Nodes

AbstractA method for completely suppressing the transient enhanced diffusion (TED) of boron implanted in preamorphized silicon is demonstrated. Boron is implanted in a molecular beam epitaxy (MBE) grown silicon sample that has been previously amorphized by silicon implantation. The sample is then annealed in order to epitaxially regrow the amorphous layer and electrically activate the dopant. The back-flow of silicon interstitials released by the preamorphization end-of-range (EOR) damage is completely trapped by a carbon-rich silicon layer interposed by MBE between the damage and the implanted boron. No appreciable TED is observed in the samples up to complete dissolution of the EOR damage, and complete electrical activation is obtained. The method might be considered for the realization of ultra shallow junctions for the far future complementary metal-oxide semiconductor technology nodes.

scholarly journals Thin Ni Silicide Formation by Low Temperature-Induced Metal Atom Reaction with Ion Implanted Amorphous Silicon

1992 ◽  
Vol 279 ◽  
Author(s):  
Yu.N. Erokhin ◽  
B. K. Patnaik ◽  
S. Pramanick ◽  
F. Hong ◽  
C. W. White ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Rutherford Backscattering Spectrometry ◽  
Silicon Layer ◽  
Amorphous Layer ◽  
Vacuum Furnace ◽  
Silicide Formation ◽  
Cross Sectional ◽  
Silicon Area ◽  
Transmission Electron ◽  
Silicide Growth

ABSTRACTWe have extended our recent work [1,2] on buried suicide formation by Ni diffusion into a buried amorphous silicon layer to the case where silicide formation is at lower temperatures on silicon substrates which have been preamorphized. The reaction of metal atoms from a 12 nm Ni film evaporated on top of a 65 nm thick surface amorphous layer formed by 35 keV Si+ ion implantation has been investigated at temperature ≤400 °C. Rutherford Backscattering Spectrometry (RBS) with channeling, cross-sectional transmission electron microscopy (XTEM), X-ray diffraction and four-point-probe measurements were used to determine the structure, interfacial morphology, composition and resistivity of the silicide films. It has been found that an increased rate of silicidation occurs for amorphous silicon with respect to crystalline areas permitting a selective control of the silicon area to be contacted during silicide growth. Vacuum furnace annealing at 360 °C for 8 hours followed by an additional step at 400 °C for one hour produces a continuos NiSi2 layer with a resistivity 44 μΩ cm.

Effect of n doped amorphous layer between microcrystalline i/n layer on the performance of micromorph tandem solar cells

2015 ◽  
Vol 1771 ◽  
pp. 9-15
Author(s):  
Jingjing Yang ◽  
Tingkai Li ◽  
Xueshi Tan ◽  
Feng Zhang ◽  
Bingxue Mao
Keyword(s):  
Solar Cells ◽  
Amorphous Silicon ◽  
Silicon Layer ◽  
Chemical Vapor ◽  
Amorphous Layer ◽  
Microcrystalline Silicon ◽  
Tandem Solar Cells ◽  
Growth Defects ◽  
Vapor Deposition Technique ◽  
Silicon Growth

ABSTRACTPin/pin “micromorph” tandem solar cells were manufactured by the industrial production line of Hunan Gongchuang PV Science & Technology Co., Ltd. Based on this kind of solar cells, a n-doped amorphous silicon layer deposited by plasma enhanced chemical vapor deposition technique (PECVD) was inserted between the microcrystalline silicon intrinsic layer and n-doped layer. The result showed that the introduced n-type amorphous silicon layer well improved the solar cells performance by reducing the bad effects caused by microcrystalline silicon growth defects. Compared with the solar cells without inserting the n-doped amorphous silicon layer, the open voltage and efficiency increased remarkably. When the thickness of n-doped amorphous silicon layer is 8nm, the open voltage increased from 72.9V to 73.6V and efficiency increased from 10.63% to 10.74%.

p-type nc-SiOx:H emitter layer for silicon heterojunction solar cells grown by rf-PECVD

2015 ◽  
Vol 1770 ◽  
pp. 7-12 ◽  
Author(s):  
Henriette A. Gatz ◽  
Yinghuan Kuang ◽  
Marcel A. Verheijen ◽  
Jatin K. Rath ◽  
Wilhelmus M.M. (Erwin) Kessels ◽  
...  
Keyword(s):  
Solar Cells ◽  
Amorphous Silicon ◽  
Material Properties ◽  
Crystalline Silicon ◽  
Silicon Layer ◽  
Nanocrystalline Silicon ◽  
Emitter Layer ◽  
Heterojunction Solar Cells ◽  
P Type ◽  
Silicon Heterojunction Solar Cells

ABSTRACTSilicon heterojunction solar cells (SHJ) with thin intrinsic layers are well known for their high efficiencies. A promising way to further enhance their excellent characteristics is to enable more light to enter the crystalline silicon (c-Si) absorber of the cell while maintaining a simple cell configuration. Our approach is to replace the amorphous silicon (a-Si:H) emitter layer with a more transparent nanocrystalline silicon oxide (nc-SiOx:H) layer. In this work, we focus on optimizing the p-type nc-SiOx:H material properties, grown by radio frequency plasma enhanced chemical vapor deposition (rf PECVD), on an amorphous silicon layer.20 nm thick nanocrystalline layers were successfully grown on a 5 nm a-Si:H layer. The effect of different ratios of trimethylboron to silane gas flow rates on the material properties were investigated, yielding an optimized material with a conductivity in the lateral direction of 7.9×10-4 S/cm combined with a band gap of E04 = 2.33 eV. Despite its larger thickness as compared to a conventional window a-Si:H p-layer, the novel layer stack of a-Si:H(i)/nc-SiOx:H(p) shows significantly enhanced transmission compared to the stack with a conventional a-Si:H(p) emitter. Altogether, the chosen material exhibits promising characteristics for implementation in SHJ solar cells.

Study on Light Induced Leakage Current Related to Amorphous Silicon TFT Design

2007 ◽  
Vol 124-126 ◽  
pp. 259-262
Author(s):  
Jae Hong Jeon ◽  
Kang Woong Lee
Keyword(s):  
Thin Film ◽  
Amorphous Silicon ◽  
Leakage Current ◽  
Thin Film Transistor ◽  
Silicon Layer ◽  
Gate Electrode ◽  
Silicon Thin Film ◽  
Pattern Design ◽  
Conventional Design ◽  
The One

We investigated the effect of amorphous silicon pattern design regarding to light induced leakage current in amorphous silicon thin film transistor. In addition to conventional design, where amorphous silicon layer is protruding outside the gate electrode, we designed and fabricated amorphous silicon thin film transistors in another two types of bottom gated structure. The one is that the amorphous silicon layer is located completely inside the gate electrode and the other is that the amorphous silicon layer is protruding outside the gate electrode but covered completely by the source and drain electrode. Measurement of the light induced leakage current caused by backlight revealed that the design where the amorphous silicon is located inside the gate electrode was the most effective however the last design was also effective in reducing the leakage current about one order lower than that of the conventional design.

scholarly journals Single Step Process for Crystalline Ni-B Compounds

Materials ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1259 ◽  
Author(s):  
Mahboobeh Shahbazi ◽  
Henrietta Cathey ◽  
Natalia Danilova ◽  
Ian Mackinnon
Keyword(s):  
Single Phase ◽  
Single Step ◽  
Transformation Mechanism ◽  
Solid Reaction ◽  
Step Method ◽  
Step Process ◽  
Pressure Time ◽  
Autogenous Pressure ◽  
Higher Temperature ◽  
High Yields

Crystalline Ni2B, Ni3B, and Ni4B3 are synthesized by a single-step method using autogenous pressure from the reaction of NaBH4 and Ni precursors. The effect of reaction temperature, pressure, time, and starting materials on the composition of synthesized products, particle morphologies, and magnetic properties is demonstrated. High yields of Ni2B (>98%) are achieved at 2.3–3.4 MPa and ~670 °C over five hours. Crystalline Ni3B or Ni4B3 form in conjunction with Ni2B at higher temperature or higher autogenous pressure in proportions influenced by the ratios of initial reactants. For the same starting ratios of reactants, a longer reaction time or higher pressure shifts equilibria to lower yields of Ni2B. Using this approach, yields of ~88% Ni4B3 (single phase orthorhombic) and ~72% Ni3B are obtained for conditions 1.9 MPa < Pmax < 4.9 MPa and 670 °C < Tmax < 725 °C. Gas-solid reaction is the dominant transformation mechanism that results in formation of Ni2B at lower temperatures than conventional solid-state methods.

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