We have demonstrated the feasibility of obtaining intense blue-to-violet electroluminescence (EL) from silicon-based light-emitting structures at room temperature (RT), in line with the need for efficient and inexpensive light sources whose production is compatible with existing silicon device technology. Ion-beam synthesis (IBS) and standard silicon processing have been used to fabricate light-emitting diodes whose active medium is a layer of thermal SiO2 containing germanium nanocrystals. Extensive research has been carried out in three main directions: optimization of the fabrication process, improvement in the device lifetime, and elucidation of the underlying mechanisms of light emission and charge injection/charge transport. This research effort has resulted in the establishment of a set of optimum conditions for the formation of improved-quality Si-based light emitters. It has been shown that the use of plasma treatement is helpful in increasing device lifetime. Issues related to the nature and the excitation of the light-emitting centers have been considered. Finally, the utility of such light-emitting devices in the development of integrated optoelectronic devices as well as Lab-on-a-Chip, microarray and sensor systems has been outlined.
Integrated optoelectronic devices are expected to become a key component of the future microelectronic and communication technology. This has led to great interest in the development of silicon-based light emitters. One of the most promising techniques for fabricating such emitters uses ion-beam synthesis (IBS) to form semiconductor nanoclusters in a layer of thermally-grown silicon dioxide. Following the preparation of metal-oxide-semiconductor (MOS) structures incorporating nanocluster-rich oxide layers, blue-to-violet electroluminescence (EL) has been observed at room temperature (RT) for implants using germanium ions and heat treatments involving furnace and/or rapid thermal processing. The power efficiency of the EL is quite high, up to 5 x 10-3, making the blue/violet light emission visible with the naked eye. It has been proven that light emission is caused by one and the same luminescent center. The microstructure of the ion-implanted and annealed oxide layers has been characterized by cross-sectional transmission electron microscopy (XTEM). The presence of second-phase nanoclusters has been found to modify considerably the charge injection and charge transport in the oxide. The optical properties of the nanocluster-rich oxide layers have been correlated with the process of charge trapping using a combination of current-voltage (I/V) and capacitance-voltage (C/V) measurements. The results obtained have enabled the nature of the EL to be elucidated. Finally, opto- and microelectronic application aspects are outlined.
New experiments are reported which explore the influence of the hydrostatic pressure during post-implantation annealing on the photoluminescence (PL) from silicon oxynitride layers (SiOxNy, x=0.25, y=1) implanted with Ge+ ions. It is shown that the use of a hydrostatic pressure during heat treatment results in an enhancement of the PL intensity by an order of magnitude compared with that arising from anneals carried out at atmospheric pressure. The observed increase in the PL intensity is explained in terms of the enhanced formation of radiative recombination canters within meta-stable regions of the implanted silicon oxynitride. The nature of these centers is believed to be associated with the equalsVSi-SiequalsV) center and defect complexes incorporating Ge atoms (e.g. equalsVSi-GeequalsV) or equalsVGe-GeequalsV) centers).
The fundamental processes that occur when SiC is implanted at elevated substrate temperatures with high doses of N+ and Al+ ions to synthesize buried layers of (SiC)x(AlN)1-x have been investigated. The influence of the mechanical stress induced by formed clusters of interstitials has been taken into account by adding a special term to the expression of current density of defects in the set of differential equations. The satisfactory agreement of simulation results and experimental data is obtained. The theoretical treatment has enabled one to determine the role of internal stress field on the evolution of defect distribution.
The (SiC)1-x(AlN)x binary system is widely investigated now. In reference 1 the possibility of using of ion implantation (Al+ and N+) in 6H-SiC under high temperatures to create (SiC)1-x(AlN)x is first reported. The samples having been heated to 200 degrees Celsius, 400 degrees Celsius, 600 degrees Celsius and 800 degrees Celsius have been irradiated by ions, and after it the RBS-profiles of generated defects have been obtained. Then the samples have been annealed at 1200 degrees Celsius and RBS- spectra have been obtained again. The main results obtained in reference 1 and 2 are presented. In reference 2 - 4 we suggested the model of defect structure evolution in silicon carbide under ion irradiation. The aim of this work is to develop this model taking into account internal stress field.
The (SiC)1(AlN) system is being extensively investigated due to the full miscibility of the two constituents, SiC and A1N, their good thermal and lattice matches, and the the possibility of modifying the band gap of the resulting structure over a wide range of 2.9 eV (6H-SiC) to 6.2 eV (2H-AIN) [1]. From a practical viewpoint, the solid solutions of SiC and A1N are promising materials for advanced high-temperature electronic and optoelectronic devices. One novel method of producing thin layers of(SiC)1(AlN) potentially suitable for microelectronic applications is the use of N and Al co-implantation into 6H-SiC at elevated temperatures followed by annealing, i.e. ion-beam synthesis. Hitherto, to the best of our knowledge, there has been only one report on the formation ofburied (SiC)1(AlN) layers in 6H-SiC by ion-beam synthesis [2]. This work is an attempt to model the fundamental processes that occur when 6H-SiC is implanted at elevated substrate temperatures with high doses of N and J ions to form thin buried layers of (SiC)1(AlN) having predetermined composition and dimensions. Results from the calculations have been correlated with those obtained by Rutherford backscattering/ channelling spectrometry (RBS/C).
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.