For strained-silicon metal-oxide-semiconductor field-effect-transistors (MOSFETs), the formation of a low-resistance source and drain region is as important in terms of enhanced performance as optimizing the strain-induced increase in inversion-carrier mobility. The crystallographic, compositional, and electrical properties of an arsenic-ion implanted strained silicon/Si0.7Ge0.3 heterostructure were investigated in order to acquire basic information for fabricating low-resistance source and drain region of the n-channel strained-silicon MOSFET. The strained-silicon layer is completely recrystallized by rapid thermal annealing after arsenic implantation, but misfit dislocations were formed by annealing (at 1000 °C) in the case thickness of the strained-silicon layer exceeding the critical thickness. Arsenic diffusivity in strained silicon was identical to that in silicon, whereas that in SiGe was higher than that in silicon. Germanium recoil and enhanced diffusion caused by arsenic implantation to the SiGe layer was observed. This phenomenon can degrade the abruptness of the strained-silicon/SiGe interface during the formation of a shallow source and drain region. Solubility limit of arsenic in strained silicon was 2×1020 cm−3 and identical to that in silicon, on the other hand, the solubility limit in Si0.7Ge0.3 reduced by half. Electron mobility in strained silicon was by about 20%–30% higher than that in silicon, and that in Si0.7Ge0.3 was by about 20%–30% lower than those in silicon. In order to reduce parasitic resistance in the shallow source and drain region, thicker strained silicon layer is thus desirable, however, it should be very careful to control the strained-silicon thickness below the critical value.

Silicon ions have been implanted into GaN layers epitaxially grown on an AlN/(0001)-Al2O3 substrate to a dose of 1×1015/cm2. The Si-implanted GaN has been rapid thermal annealed at temperatures between 800 and 1250 °C. Thermal pits are formed in the surface during annealing at 1200 °C, resulting in deterioration of the morphology. The surface deterioration is effectively suppressed by using a 140-nm-thick Si3N4 film as an encapsulant during annealing up to 1250 °C. The electrical activation process for Si atoms has an activation energy of 3.1 eV in the range of 1000 to 1250 °C. Carrier concentration and mobility profiles for n-type layers formed by Si implantation have been examined by differential Hall-effect measurements. A very high electrical activity for implanted Si atoms of 86% can be achieved, and a highly doped n-type layer with a peak carrier concentration of 6×1019/cm3 is formed after annealing at 1250 °C. Electrons generated from Si atoms located near the end of range are trapped by defects remaining after annealing at 1250 °C.

A surface reaction model for boron and phosphorus atoms on silicon during vapor-phase doping is proposed by calculating their sticking coefficients. In boron doping, two sticking configurations are found: a low B2H6-concentration case, and a high B2H6-concentration case. In the low B2H6- concentration case, a low sticking coefficient is maintained during doping, and in which hydrogen desorption from the surface opens more sites for boron chemisorption. In the high B2H6-concentration case, excessively chemisorbed boron atoms react with each other, causing boron segregation. A low sticking coefficient is preferred in order to avoid boron segregation and to control the concentration. In the phosphorus doping, the sticking coefficient was much lower than that of boron, and phosphorus does not segregate on silicon.

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Radiation damages created in silicon single crystals bombarded with 10-keV aluminum ions were examined by means of electron diffraction method. A deep penetration of aluminum ion in silicon was observed, extending to 0.58 μ. This penetration was depressed by removing the bombarded surface layer about 800 Å in thickness before annealing. From these results, we interpret the deep penetration as a radiation enhanced diffusion effect.

Boron atoms are incorporated into (100)Si wafers by heating the substrates at 800 °C for 30 min in a (B2H6+H2) atmosphere and by subsequent rapid thermal annealing above 900 °C. Atomic and carrier-concentration profiles of boron-doped layers have been examined by a secondary-ion mass spectrometry and by differential Hall measurements, respectively. Experimental results have clearly shown that ultrashallow p+ layers, 300 Å thick, with a surface carrier concentration of 7.26×1019/cm3 can be formed by diffusion of boron at 800 °C and by subsequent RTA at 100 °C.

Molecular N ions (N+2) have been implanted at an incident energy of 30 keV in a heteroepitaxial β-SiC layer grown on a (100)-Si substrate to form an n+ layer in the substrate. Furnace and rapid-thermal annealing are carried out on N-implanted substrates. Crystalline properties of the implanted layers have been characterized by Rutherford backscattering measurements and transmission electron microscope observations. An anodic oxide growth and removal technique has been developed, by which a very thin SiC layer can be reproducibly stripped from the substrate. Carrier-concentration and mobility profiles for n-type layers formed under various implant and annealing conditions have been investigated by differential Hall measurements combined with the layer stripping process. Rutherford backscattering data indicate that heating of substrate during implantation is important to reduce the amount of defects existing in the substrate after annealing. It has been revealed that rapid thermal annealing is useful for achieving high electrical activation of implanted N atoms. A very shallow (<100 nm) n+ layer with a maximum carrier concentration of around 1×1020/cm3 can be formed in the SiC layer by N implantation at 400 °C and by subsequent rapid thermal annealing at 1100 °C for 10 s. This highly doped layer is applicable to an emitter in a SiC/Si heterobipolar transistor. It has been also shown that implantation with a very high dose, e.g., 1.2×1016/cm2, gives rise to the formation of Si3N4 in the substrate after annealing, suppressing electrical activation of implanted atoms.