30 research outputs found
Effects of heat-treatments on electrical properties of boron-doped silicon crystals
The effects of heat-treatments around 1000°Cand subsequent annealing on the electrical properties of boron-doped
silicon have been studied by electrical conductivity, Hall effect, and deep-level transient spectroscopy measurements. The
high-temperature heat-treatments always induced net densities of donors. Four recovery stages, stages I-IV, of heat-treatment-
induced donors were observed on isochronal annealing up to 400°C Conductivity changes in these stages can be explained
as described below by the reactions of interstitial iron (Fei), its pair (Fe1Bs)with substitutional boron (Bs), and two
unknown donors (D1, D2). That is, stage I (25°-100°C):
D1→sink and Fei + Bs→FeiBs, stage II (100°-150°C):
FeiBs→Fei + Bs, stage III (200°-250°C):D2→sink, stage IV (250°-350°C)Fei→precipitation. Heat-treatments in an oxygen
atmosphere greatly reduced the introduction of Fei and FeiBs in comparison with an argon atmosphere and mainly introduced
D1 and D2 donors. The density of D2 was dependent on the heat-treatment temperature, while that of D1 showed almost
no dependence. In stage I, D, was annihilated by first-order kinetics with an activation energy of 0.8 eV. It was indicated
that DI and D2 have no relations to iron, copper, oxygen, nor carbon. Though their origins are still unidentified, there
may be some interstitial impurities. In stage IV, Fei is suggested to precipitate at oxygen precipitates and dislocation loops
formed by high-temperature heat-treatments. As to the application to iron gettering in the device fabrication process, it is
proposed that annealing around 300°C is most suitable as the final heat-treatment step to remove iron and related defects
from active regions of devices.
Silicon wafers receive complex heat-treatments at various.</p
Characterization of polycrystalline tungsten surfaces irradiated with nitrogen ions by X-ray photoelectron spectroscopy
olycrystalline tungsten surfaces were irradiated at room temperature with two kinds of nitrogen ions N+ and N2+̶ at 2.5 keV by using an ion beam apparatus. Results of X-ray photoelectron spectroscopy (XPS) experiments performed using synchrotron radiation at SPring-8 showed that upon irradiation of the tungsten sample with either kind of ion, the full widths at half maximum (FWHM) of the W 4f7/2 and W 4f5/2 peaks broadened and the peaks at 35.8 eV and 37.8 eV which correspond to WO3 binding energies increased slightly; this indicated the formation of tungsten nitride at the subsurface below the interface