Internal Gettering of Copper for Microelectronic Applications

Kissinger, G.; Kot, Dawid; Schubert, Markus Andreas; Sattler, Andreas; Müller, Timo

doi:10.4028/www.scientific.net/ssp.242.236

Cited by 6 publications

(7 citation statements)

References 36 publications

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“…37 It is very unlikely that this is based on nucleation of copper silicide precipitates because of the low temperature and the low supersaturation. Segregation effects become more pronounced with decreasing temperature and segregation gettering would still work.…”

Section: Discussionmentioning

confidence: 99%

Investigation of the Copper Gettering Mechanism of Oxide Precipitates in Silicon

Kissinger

Kot

Klingsporn

et al. 2015

ECS J. Solid State Sci. Technol.

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One of the reasons why the principal gettering mechanism of copper at oxide precipitates is not yet clarified is that it was not possible to identify the presence and measure the copper concentration in the vicinity of oxide precipitates. To overcome the problem we used a 14.5 nm thick thermal oxide layer as a model system for an oxide precipitate to localize the place where the copper is collected. We also analyzed a plate-like oxide precipitate by EDX and EELS and compared the results with the analysis carried out on the oxide layer. It is demonstrated that both the interface between the oxide precipitate being SiO 2 and the silicon matrix and the interface between the thermal oxide and silicon consist of a 2-3 nm thick SiO layer. As the results of these experiments also show that copper segregates at the SiO interface layer of the thermal oxide it is concluded that gettering of copper by oxide precipitates is based on segregation of copper to the SiO interface layer.

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Section: Discussionmentioning

confidence: 99%

Investigation of the Copper Gettering Mechanism of Oxide Precipitates in Silicon

Kissinger

Kot

Klingsporn

et al. 2015

ECS J. Solid State Sci. Technol.

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“…[2][3][4] It was also demonstrated that metallic impurities can be effectively trapped at oxygen precipitates in the process of gettering. [5][6][7][8][9] All these features of the oxygen precipitates require the control of precipitation in the production process of silicon devices. However, this cannot be optimally executed if the features of oxygen precipitates like their composition are not fully known.…”

mentioning

confidence: 99%

Current Stage of the Investigation of the Composition of Oxygen Precipitates in Czochralski Silicon Wafers

Kot

Kissinger

Schubert

et al. 2017

ECS J. Solid State Sci. Technol.

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In this work, we look on the current stage of the investigation of the composition of oxygen precipitates obtained with the help of different techniques. Moreover, we present our recent and new investigation of the composition of oxygen precipitates carried out by means of energy dispersive X-ray spectroscopy, electron energy loss spectroscopy, and Fourier transform infrared spectroscopy. The FTIR spectra measured at liquid helium temperature are compared with the spectra simulated on the basis of experimental results obtained by scanning transmission electron microscopy. Oxygen precipitates formed in Czochralski (CZ) silicon wafers in consequence of the thermal treatment were investigated since many decades (see e.g. Ref. 1). The main reason why so much effort was directed toward these defects was the impact which they have on integrated circuits and the properties of the silicon wafer itself. Oxygen precipitates can increase the resistivity of CZ silicon, change the wafer strength and cause warpage of the wafers. [2][3][4] It was also demonstrated that metallic impurities can be effectively trapped at oxygen precipitates in the process of gettering. [5][6][7][8][9] All these features of the oxygen precipitates require the control of precipitation in the production process of silicon devices. However, this cannot be optimally executed if the features of oxygen precipitates like their composition are not fully known. In spite of the wide knowledge about oxygen precipitation, the composition of oxygen precipitates SiO x still remains under ongoing discussion. This is due to the different x values varying from x = 1 to x = 2 which can be found in the literature. [10][11][12][13][14][15][16][17][18][19][20] In 1986, Skiff et al. investigated plate-like precipitates by electron energy loss spectroscopy (EELS) in the near-edge and ionization edge range. 10 The composition which they found was SiO 0.95 . At the beginning of the 90ies, Borghesi et al. modeled Fourier transform infrared spectroscopy (FTIR) spectra by an effective medium approach and concluded that the absorption band of precipitates at 1230 cm −1 can be well reproduced if SiO 1.8 is used.11 However, in 1995 Vanhellemont investigated the growth kinetics of oxygen precipitates based on the solubility and diffusivity of oxygen in silicon using precipitate sizes determined by transmission electron microscopy (TEM). He demonstrated that the precipitated phase is closer to SiO than to SiO 2 .12 The later works, exploiting again FTIR spectroscopy and effective medium theory for the determination of the composition of the oxygen precipitates and carried out by De Gryse et al., confirmed the thesis of Vanhellemont. In the beginning the authors obtained SiO x with x = 1.1-1.2 but in their more recent work they modified the algorithm and concluded that the precipitated phase behaves optically as a mixture of amorphous silicon and amorphous SiO 2 .13,14 Meduňa et al. investigated the composition of oxygen precipitates in silicon wafers characterized by different th...

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“…A concentration‐dependent gettering efficiency was already observed for other transition metals such as copper. [ 14 ]…”

Section: Resultsmentioning

confidence: 99%

“…A concentration-dependent gettering efficiency was already observed for other transition metals such as copper. [14] Table 1. Backside layers and resistivity of the specimens.…”

Section: Resultsmentioning

confidence: 99%

Internal and External Gettering of Iron Contamination in Power Technologies

Frascaroli

Roffarello

Mica

2021

Physica Status Solidi (a)

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Substrate gettering and the contribution to the contamination reduction of backside layers are evaluated after high‐temperature annealing, following intentional iron contamination at the backside in silicon epitaxial wafers typical of power technologies. Iron is detected at the frontside by deep‐level transient spectroscopy within a depth corresponding to the actual devices. Herein, contamination occurring at the beginning of the semiconductor process flow is simulated and the role of the different gettering mechanisms is isolated. Substrate boron in epitaxial p over p+ wafers is effective in more than halving iron contamination at the front compared with a p‐only substrate, especially at high contamination doses. In the absence of a specific thermal cycle for oxygen precipitation and growth in the bulk, long thermal treatment at 1200 °C induces a significant precipitate growth even in the beginning of the process, greatly contributing to iron gettering in the bulk. However, this effect is found to strongly depend on the silicon condition after crystal growth. No significant contribution to iron gettering from a backside polycrystalline silicon layer is found after high‐temperature annealing, whereas a backoxide acts as diffusion barrier, effectively screening the substrate from contamination only for short thermal treatments or annealing temperature below 1000 °C.

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Internal Gettering of Copper for Microelectronic Applications

Cited by 6 publications

References 36 publications

Investigation of the Copper Gettering Mechanism of Oxide Precipitates in Silicon

Investigation of the Copper Gettering Mechanism of Oxide Precipitates in Silicon

Current Stage of the Investigation of the Composition of Oxygen Precipitates in Czochralski Silicon Wafers

Internal and External Gettering of Iron Contamination in Power Technologies

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