Effect of Heavy Boron Doping on Oxide Precipitate Growth in Czochralski Silicon

Abstract

Oxide precipitate growth in boron‐doped Czochralski silicon wafers with resistivities ranging from 6 to 40 mΩ cm has been studied following prolonged annealing from 800 to 1000°C. Transmission electron microscopy revealed that (i) the growth rate of oxide platelet precipitates is proportional to the square root of time in 40 mΩ cm samples and (ii) the precipitate morphology changes from plate to polyhedral and strain around the precipitate decreases during annealing at 900°C in 6, 9, and 18 mΩ cm samples. These results indicate that changes in precipitate morphology occur because the oxygen precipitation and boron atom size effects are enhanced by increasing boron concentration. © 1999 The Electrochemical Society. All rights reserved.

Characterization of Oxide Precipitates in Heavily B-Doped Silicon by Infrared Spectroscopy

“…Although relatively well understood in moderately doped silicon, oxygen precipitation kinetics and precipitate morphology are strongly different in low-resistivity silicon. [1][2][3][4] To use the internal gettering properties of oxide precipitates in a controlled way, a quantitative understanding of oxygen precipitation and of the chemical composition of the oxide precipitates in heavily doped silicon is needed.…”

Optical spectroscopy of oxygen precipitates in heavily doped p-type silicon

“…In addition, some new peaks at ∼845 and 796 meV may develop for the 'lightly' doped samples B12 and B14 studied here. In order to interpret the data more clearly, the PL results of table 2 are compared with the results revealed by the FTIR analysis and the findings summarized in table 3. More details will be published elsewhere [16].…”

“…It remains to explain the impact of the B concentration on the oxygen precipitation behaviour. In this context, it should be noted that the presence of a high boron concentration has a strong effect on the strain relaxation around an oxide precipitate, which results in a change in the precipitate morphology from platelike to polyhedral and the emission of silicon interstitials [3]. It is, therefore, expected that precipitate strain relaxation by interstitial injection in the matrix will happen earlier for the less heavily doped material B12-B14 compared with B3-B6.…”

Growth and nucleation regimes in boron doped silicon by dynamical x-ray diffraction

“…For B concentrations significantly lower than the O content (pÀ), the precipitation behavior seems to be unaffected. [10][11][12] Several authors report an enhanced nucleation rate [13][14][15][16] in a temperature range from 700 to 850 C in case the amount of B exceeds the O concentration (pþ), whereas the growth kinetics at 1050 C remains unaffected. 15 Explanations for a higher SiO x density in pþ material vary.…”

“…[10][11][12] Several authors report an enhanced nucleation rate [13][14][15][16] in a temperature range from 700 to 850 C in case the amount of B exceeds the O concentration (pþ), whereas the growth kinetics at 1050 C remains unaffected. 15 Explanations for a higher SiO x density in pþ material vary. The most prominent models involve heterogeneous nucleation on B 2 O 3 clusters 13,17 and B enhanced O dimer diffusion.…”