Ion implantation is being applied extensively to silicon device technology. Two principle features are utilized- 1) charge control in MOS structures for threshold shift, autoregistration, and complementary wells and 2) distribution control in microwave and bipolar structures. Another feature that has not been extensively exploited is to combine the advantages of the high resolution capabilities of electric beam pattern delineation with the low lateral spread inherent in the implantation process. This talk reviews some of the general features of the characteristics of implanted layers in terms of depth distribution, radiation damage and electron activity. Implantation processes in silicon are reasonably well understood. There remain areas which require further clarification. For compound semiconductors, particularly GaAs, implantation techniques offer attractive possibilities for the fabrication of high frequency devices. In these materials, the substrate temperature during implantation and the dielectric coating required to prevent dissociation during thermal anneal play major roles.

Ion implantation in semiconductors

Ion Implantation in Semiconductors

This paper reviews the basic physical mechanisms of the interactions of ionizing radiation with MOS oxides, including charge generation, transport, trapping and detrapping, and interface trap formation. Device and circuit effects are also discussed briefly.

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Total ionizing dose effects in MOS oxides and devices

Implanted B and P dopants in Si exhibit transient enhanced diffusion (TED) during annealing which arises from the excess interstitials generated by the implant. In order to study the mechanisms of TED, transmission electron microscopy measurements of implantation damage were combined with B diffusion experiments using doping marker structures grown by molecular-beam epitaxy (MBE). Damage from nonamorphizing Si implants at doses ranging from 5×1012 to 1×1014/cm2 evolves into a distribution of {311} interstitial agglomerates during the initial annealing stages at 670–815 °C. The excess interstitial concentration contained in these defects roughly equals the implanted ion dose, an observation that is corroborated by atomistic Monte Carlo simulations of implantation and annealing processes. The injection of interstitials from the damage region involves the dissolution of {311} defects during Ostwald ripening with an activation energy of 3.8±0.2 eV. The excess interstitials drive substitutional B into electric...

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Physical mechanisms of transient enhanced dopant diffusion in ion-implanted silicon

This paper provides a historical review of the literature on the effects of radiation-induced displacement damage in semiconductor materials and devices. Emphasis is placed on effects in technologically important bulk silicon and silicon devices. The primary goals are to provide a guide to displacement damage literature, to offer critical comments regarding that literature in an attempt to identify key findings, to describe how the understanding of displacement damage mechanisms and effects has evolved, and to note current trends. Selected tutorial elements are included as an aid to presenting the review information more clearly and to provide a frame of reference for the terminology used. The primary approach employed is to present information qualitatively while leaving quantitative details to the cited references. A bibliography of key displacement-damage information sources is also provided.

Review of displacement damage effects in silicon devices

We have studied the thermal stability of Si1−yCy/Si (y=0.007 and 0.014) heterostructures formed by solid phase epitaxial regrowth of C implanted layers. The loss of substitutional C was monitored over a temperature range of 810–925 °C using Fourier transform infrared absorbance spectroscopy. Concurrent strain measurements were performed using rocking curve x‐ray diffraction to correlate strain relaxation with the loss of substitutional C from the lattice. Loss of C from the lattice was initiated immediately without an incubation period, indicative of a low barrier to C clustering. The activation energy as calculated from a time to 50% completion analysis (3.3±5 eV) is near the activation energy for the diffusion of C in Si. Over the entire temperature range studied, annealing to complete loss of substitutional C resulted in the precipitation of C into β‐SiC. The precipitates are nearly spherical with diameters of 2–4 nm. These precipitates have the same crystallographic orientation as the Si matrix but th...

Precipitation and relaxation in strained Si1−yCy/Si heterostructures

We report the synthesis and detailed structural characterization of SiGeC metastable alloys formed by solid phase epitaxial regrowth Epitaxial layers with 07 and 14 at % C are formed by 700 °C regrowth of multiple energy carbon implants into preamorphized Si086Ge014 layers on Si substrates Transmission electron microscopy and Rutherford backscattering spectrometry show heteroepitaxial regrowth of Si1−x−yGexCy layers into the metastable diamond cubic phase Fourier transform infrared spectroscopy verifies that the carbon occupies substitutional lattice sites Double crystal x‐ray diffraction measurements of Si1−x−yGexCy and Si1−yCy reference layers quantify the C‐induced tensile strain component This strain compensates for the compressive strain in the SiGe layers, and indicates a change in lattice constant per atomic fraction C in agreement with Vegard’s law

Metastable SiGeC formation by solid phase epitaxy

We have studied the incorporation of heavily supersaturated C into Si using solid‐phase epitaxy (SPE) of implanted amorphous layers. The strain in the Si1−xCx/Si heterostructures was measured using rocking curve x‐ray diffraction. The microstructure and defect introduction were examined using ion channeling and transmission electron microscopy (TEM). The fraction of C located on substitutional lattice sites in the Si was monitored using Fourier transform infrared absorption spectroscopy and ion channeling at resonance energies. Carbon‐depth profiles were monitored by secondary ion mass spectroscopy. The metastable solubility limit for the incorporation of C into Si by SPE was found to be 3.0–7.0×1020 atoms/cm3, which is over three orders of magnitude above the equilibrium solubility at the Si melting point. This limit was determined by the ability to regrow without the introduction of microtwins and stacking faults along {111} planes. We postulate the local bond deformation resulting from the atomic size ...

Carbon incorporation into si at high concentrations by ion implantation and solid phase epitaxy

Hole and electron transport are reported for three different kinds of MOS oxides: wet, dry, and ion-implanted. The electron-hole pairs are generated in the bulk of the oxide by a 3 ns x-ray pulse and the separation of the electron and hole photocurrents is made possible by the large difference in mobility. The electrons are so mobile that they are swept from the oxide (or trapped in a heavily ion-implanted region) during the x-ray pulse. The holes, on the other hand, have much lower mobilities which depend strongly on the preparation of the oxide. In the dry oxide the nominal mobility at room temperature is several orders of magnitude higher than in the wet oxide. The mobility is strongly activated by temperature in the oxides, and at liquid N$sub 2$ temperature no hole motion could be detected even though the electrons are still swept out. The low temperature charging of oxides can be understood in terms of the bulk trapped holes, but room temperature charging seems to be dominated by trapping close to the Si/SiO$sub 2$ interface rather than the transport of the holes from the bulk to the interface. Ion implantation provides electron traps which seem to be associatedmore » with the lattice damage rather than the ion. The electron traps can be successfully annealed out at 900$sup 0$C in 20 minutes. (auth)« less

H. J. Stein

Papers

Precipitation and relaxation in strained Si1−yCy/Si heterostructures

Metastable SiGeC formation by solid phase epitaxy

Carbon incorporation into si at high concentrations by ion implantation and solid phase epitaxy

Hole Transport in MOS Oxides

ELECTRICAL STUDIES OF NEUTRON-IRRADIATED n-TYPE Si: DEFECT STRUCTURE AND ANNEALING.