Defect Density in Doped a-Si:H Films

1990 ◽  
Vol 192 ◽  
Author(s):  
K. Pierz ◽  
H. Mell ◽  
W. Fuhs
Keyword(s):  
Thermal Equilibrium ◽  
Defect Density ◽  
Electronic Energy ◽  
Dangling Bond ◽  
Thermal Equilibrium State ◽  
Boron Doped ◽  
Atomic Spacing ◽  
P Type ◽  
Defect Reaction ◽  
Positively Charged

ABSTRACTWe compare the experimentally observed correlation between the density of charged dangling–bond defects and the Fermi–level position in n– and p–type a–Si:H films with the predictions of two hydrogen–related models for the thermal equilibrium state at the glass–transition temperature of the hydrogen glass in a–Si:H. Reasonable agreement is obtained with a defect reaction in which the transfer of hydrogen from Si–H bonds to weak bonds is limited to distances comparable to one atomic spacing. The results for p–type (boron–doped) films suggest that the formation of positively charged dangling–bond defects is not only determined by electronic energy differences but also by a relaxational energy gain of approximately 0.2eV.

Electron Paramagnetic Resonance Study of Carbon Antisite-Vacancy Pair in p-Type 4H-SiC

2007 ◽  
Vol 556-557 ◽  
pp. 453-456 ◽  
Author(s):  
T. Umeda ◽  
Norio Morishita ◽  
Takeshi Ohshima ◽  
Hisayoshi Itoh ◽  
Junichi Isoya
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Electron Irradiation ◽  
Electron Paramagnetic Resonance Study ◽  
Dangling Bond ◽  
Charged State ◽  
Paramagnetic Resonance ◽  
Vacancy Pair ◽  
P Type ◽  
Electron Paramagnetic ◽  
Positively Charged

Carbon antisite-vacancy pair (CSiVC) is a fundamental defect in SiC, and is theoretically predicted to be very stable in p-type materials. However, this pair was found only in the form of a negatively charged state (i.e., the SI5 center = CSiVC −) in n-type and semi-insulating 4H-SiC, and yet, its presence has not been shown in p-type SiC. In this report, we present the first EPR observation on positively charged CSiVC pairs in p-type 4H-SiC. By carefully examining p-type samples after electron irradiation, we found a pair of new defects with C3v and C1h symmetries. They correspond to “c-axial” pairs (C3v) and “basal” pairs (C1h) of CSiVC +, respectively. The positively charged pairs are characterized by a strong 13C hyperfine interaction due to a dangling bond on a carbon antisite (CSi), which is successfully resolved for the c-axial pairs.

Diffusion of Gold into Heavily Boron-Doped Silicon

1997 ◽  
Vol 469 ◽  
Author(s):  
H. Bracht ◽  
A. Rodriguez Schachtrup
Keyword(s):  
Doping Level ◽  
Hole Concentration ◽  
Effective Diffusion ◽  
Boron Doped ◽  
Enthalpy Difference ◽  
Background Doping ◽  
B Doping ◽  
P Type ◽  
Level Effect ◽  
Positively Charged

ABSTRACTDiffusion of Au into dislocation-free and highly dislocated Si with high B-background doping levels has been investigated with the aid of neutron activation analysis in conjunction with mechanical sectioning. The high B-doping level causes extrinsic conditions, i.e., the hole concentration exceeds the intrinsic carrier concentration even at diffusion temperatures between 900°C and 1100°C. All profiles are accurately described on the basis of the kick-out diffusion model and a mechanism which takes into account segregation of Au at dislocations. Our analysis provides solubility data of Au in Si and effective diffusion coefficients related to interstitial Au and Si self-interstitials I. The dependence of these quantities on the B-background doping level is well described by the Fermi-level effect. This analysis supports singly positively charged states in p-type Si of Au on interstitial (Aui) and substitutional (Aus) sites and of Si self-interstitials. Successful fitting of additionally requires an acceptor level of Aus. The electrical properties deduced for Aui, Aus and I are summarized in Table 2. Au profiles in highly dislocated Si obtained especially after diffusion at 900° C give evidence of Au trapped at dislocations. From our preliminary experimental results we determine an enthalpy difference of 2.7 eV between Au on substitutional sites and Au captured at dislocations.

Electrical properties of boron doped CVD diamond after plasma cleaning probed by capacitance-voltage profiling

2014 ◽  
Vol 1634 ◽  
Author(s):  
Luana S. Araujo ◽  
Olivia Berengue ◽  
Maurício Baldan ◽  
Neidenei Ferreira ◽  
João Moro ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Chemical Vapor ◽  
Diamond Surface ◽  
Plasma Cleaning ◽  
Electrical Characteristics ◽  
Capacitance Measurements ◽  
Boron Doped ◽  
Capacitance Voltage ◽  
Surface Adsorbates ◽  
P Type

ABSTRACTDoped diamond films grown by chemical vapor techniques has been used to study hydrogen and oxygen terminated diamond. It is known that the electrical characteristics of metal-diamond interface are strongly affected by the diamond surface features. O2 plasma treatment was used as a cleaning procedure for as grown diamond samples leading to changes in the capacitance measurements after treatment. The alteration in the characteristics of the samples can be attributed to the surface adsorbates like hydrogen and water vapor present in the atmosphere. The results indicates that the O2 plasma treatment was effective in cleaning the surface revealing the expected features of a p-type diamond film.

scholarly journals Self- and Dopant Diffusion in Extrinsic Boron Doped Isotopically Controlled Silicon Multilayer Structures

2002 ◽  
Vol 719 ◽  
Author(s):  
Ian D. Sharp ◽  
Hartmut A. Bracht ◽  
Hughes H. Silvestri ◽  
Samuel P. Nicols ◽  
Jeffrey W. Beeman ◽  
...  
Keyword(s):  
Multilayer Structure ◽  
Secondary Ion Mass Spectrometry ◽  
Diffusion Processes ◽  
Quantitative Description ◽  
Multilayer Structures ◽  
Dopant Diffusion ◽  
Enhanced Diffusion ◽  
Self Diffusion ◽  
Boron Doped ◽  
P Type

AbstractIsotopically controlled silicon multilayer structures were used to measure the enhancement of self- and dopant diffusion in extrinsic boron doped silicon. 30Si was used as a tracer through a multilayer structure of alternating natural Si and enriched 28Si layers. Low energy, high resolution secondary ion mass spectrometry (SIMS) allowed for simultaneous measurement of self- and dopant diffusion profiles of samples annealed at temperatures between 850°C and 1100°C. A specially designed ion-implanted amorphous Si surface layer was used as a dopant source to suppress excess defects in the multilayer structure, thereby eliminating transient enhanced diffusion (TED) behavior. Self- and dopant diffusion coefficients, diffusion mechanisms, and native defect charge states were determined from computer-aided modeling, based on differential equations describing the diffusion processes. We present a quantitative description of B diffusion enhanced self-diffusion in silicon and conclude that the diffusion of both B and Si is mainly mediated by neutral and singly positively charged self-interstitials under p-type doping. No significant contribution of vacancies to either B or Si diffusion is observed.

New experiments on the relationship between light-induced defects and photoconductivity degradation

2001 ◽  
Vol 664 ◽  
Author(s):  
Stephan Heck ◽  
Howard M. Branz
Keyword(s):  
Activation Energy ◽  
Defect Density ◽  
Activation Energies ◽  
Dangling Bond ◽  
Fast Recovery ◽  
Slow Recovery ◽  
Degradation Model ◽  
Induced Defects ◽  
The Relationship ◽  
Hydrogenated Amorphous

ABSTRACTWe report experimental results that help settle apparent inconsistencies in earlier work on photoconductivity and light-induced defects in hydrogenated amorphous silicon (a-Si:H) and point toward a new understanding of this subject. After observing that light-induced photoconductivity degradation anneals out at much lower T than the light-induced increase in deep defect density, Han and Fritzsche[1] suggested that two kinds of defects are created during illumination of a-Si:H. In this view, one kind of defect degrades the photoconductivity and the other increases defect sub-bandgap optical absorption. However, the light-induced degradation model of Stutzmann et al.[2] assumes that photoconductivity is inversely proportional to the dangling-bond defect density. We observe two kinds of defects that are distinguished by their annealing activation energies, but because their densities remain in strict linear proportion during their creation, the two kinds of defects cannot be completely independent.In our measurements of photoconductivity and defect absorption (constant photocurrent method) during 25°C light soaking and during a series of isochronal anneals between 25 < T < 190°C, we find that the absorption measured with E ≤1.1 eV, first increases during annealing, then exhibits the usual absorption decrease found for deeper defects. The maximum in this absorption at E ≤1.1eV occurs simultaneously with a transition from fast to slow recovery of photoconductivity. The absorption for E ≤1.1eV shows two distinct annealing activation energies: the signal rises with about 0.87 eV and falls with about 1.15 eV. The 0.87 eV activation energy roughly equals the activation energy for the dominant, fast, recovery of photoconductivity. The 1.15 eV activation energy roughly equals the single activation energy for annealing of the light-induced dangling bond absorption.

Simultaneous Relaxation of Network and Defects in Silicon-Implanted a-Si:H

1995 ◽  
Vol 377 ◽  
Author(s):  
J. Nakata ◽  
S. Sherman ◽  
S. Wagner ◽  
P. A. Stolk ◽  
J. M. Poate
Keyword(s):  
Electronic Transport ◽  
Annealing Temperature ◽  
Urbach Energy ◽  
Defect Density ◽  
Dark Conductivity ◽  
Equilibrium Theory ◽  
Hopping Conduction ◽  
Dangling Bond ◽  
Bond Density ◽  
Additional Illumination

ABSTRACTWe report extensive optical and electronic transport data on silicon-implanted a-Si:H, annealed in steps in the dark or with additional illumination. All measured properties relax gradually with increasing annealing temperature. The dark conductivity of the as-implanted film is dominated by hopping conduction via midgap defects. This channel is pinched off during the initial stages of annealing. The midgap defect density and the Urbach energy follow an annealing path that agrees qualitatively with the trajectory postulated by the equilibrium theory of the dangling-bond density. Therefore, the silicon network and the defect density equilibrate continuously during network relaxation.

Photovoltaic Characterization of Trapping in Porous Silicon

1994 ◽  
Vol 358 ◽  
Author(s):  
D. W. Boeringer ◽  
R. Tsu
Keyword(s):  
Porous Silicon ◽  
Photovoltaic Effect ◽  
Light Spot ◽  
Dangling Bond ◽  
Photogenerated Electrons ◽  
Device Applications ◽  
Photovoltaic Characterization ◽  
P Type ◽  
Silicon Based ◽  
Position Sensitive Detectors

ABSTRACTWe report the first observation of the lateral photovoltaic effect in porous silicon. Contacts placed on either side of a porous silicon region develop a voltage up to several millivolts if the sample is asymmetrically illuminated. If the light spot is closer to one contact, the voltage will have one polarity; if it is closer to the other contact, the polarity will be opposite. In the case of n-type, the contact nearest the light spot is positive; for p-type, the contact nearest the light spot is negative In the region between the contacts, the photovoltage varies almost linearly with the position of the light spot, over a distance 4.5 cm across. The origin of our lateral photoeffect may be explained by the trapping of photoexcited carriers by a pair of dangling bond centers in porous silicon. In the case of p-type, the photogenerated electrons are trapped by the dangling bond states while holes diffuse away in the substrate. The situation for n-type is opposite; holes are trapped by the dangling bond states while electrons diffuse away in the substrate. This differs from the conventional lateral photoeffect, which arises under the nonuniform illumination of a junction between two layers of differing conductivities. Hamamatsu sells silicon-based position-sensitive detectors with a resolution down to 0.1 µm. The possibility of using this lateral photoeffect to characterize these dangling bond states in porous silicon as well as several possible device applications will be discussed.

Sign in / Sign up

Export Citation Format

Share Document