Diffusion doping of silicon with magnesium

Abstract

Doping of silicon with magnesium is investigated by a sandwich diffusion technique. Temperature dependence of the diffusion coefficient in the dislocation-free silicon in the range of 1000-1200 8C is determined. It obeys the Arrhenius behavior over the range of 600-1200 8C, when the data obtained earlier for the lower temperatures are taken into consideration. Preliminary results on Mg diffusion in the dislocated crystals are also presented. The dislocation-free Si:Mg samples are investigated with the Hall-effect measurements and the low-temperature Fourier spectroscopy. A decrease in concentration of Mg interstitials (about 15%) has been observed after 31 months of the samples storage at room temperature, when a commercially available FZ silicon was used as a starting material. The effect of the samples degradation is proposed to be due to a formation of Mg-O complexes. When using a special silicon purified from oxygen and carbon with concentrations below or equal to 1.5 Â 10 14 and 5 Â 10 14 cm À3 , respectively, a decrease in the density of interstitial magnesium has not been noticed during this period. The storage of Si:Mg samples prepared from pure silicon gives rise to the formation of an unknown center, whose ionization energy is between the corresponding values for the interstitial Mg 0 centers and (Mg-O) 0 complexes.

Even‐Parity Excited States in Infrared Emission, Absorption, and Raman Scattering Spectra of Shallow Donor Centers in Silicon

“…Magnesium doped crystals have been obtained by high temperature diffusion employing a "sandwich" technique, see for details ref. [12].…”

Radii of Rydberg states of isolated silicon donors

“…We investigated the QZE in bulk-doped silicon with single substitutional donors Bi, Sb or P [35,36], the single interstitial donor Li, substitutional double donors S [37,38] and Se [33,39], the interstitial double donor Mg [40], and double donor complexes S 2 and Se 2 . The doping of each was in the range 1 × 10 14 −2 × 10 15 cm −3 , low enough that the distance between the donors is far larger than the orbit radius of any of the states of interest.…”

Mg diffusion in Si on a thermodynamic basis

“…The defect processes of magnesium (Mg) in Si have been studied for numerous years [9][10][11][12][13]. From a technological viewpoint the interest is driven by the potential application of Mg-doped Si in photonic devices [14].…”

“…Interestingly, it was determined by Sigmund that the concentration of Mg can be up to 10 19 cm −3 at 1200 °C [17]. Recent experimental diffusion studies in dislocation free Mg-doped Si employed the p-n junction method and Hall measurements to indicate that mainly Mg i migrate [12,13].…”

“…In the present study, the recently reported experimental data [12,13] on diffusion of Mg in Si in the temperature range, 873-1473 K are analyzed in the framework of the cBΩ model. Based on reported elastic and expansion properties of Si, we calculate the corresponding temperature dependence of various point defect thermodynamic parameters such as activation enthalpy, activation Gibbs free energy, activation entropy, activation volume and specific heat of activation.…”