- Email: [email protected]
Effect of high temperature - pressure on SOI structure
Crystal Engineering 5 (2002) 155–161 www.elsevier.com/locate/cryseng
Effect of high temperature - pressure on SOI structure A. Misiuk a,∗, L. Bryja b, J. Bak-Misiuk c, J. Ratajczak a, I.V. Antonova d, V.P. Popov d a Institute of Electron Technology, Al. Lotnikow 46, 02-668 Warsaw, Poland Wroclaw University of Technology, Wyb. Wyspianskiego 27, 50-370 Wroclaw, Poland c Institute of Physics, PAS, Al. Lotnikow 32/46, 02-668 Warsaw, Poland d Institute of Semiconductor Physics, RAS, Lavrentieva 13, 630090 Novosibirsk, Russia
b
Abstract Silicon on insulator (SOI) structures (Si / SiO2 layer / Si) were prepared by bonding the oxidised Si wafer with the hydrogen implanted one and a cleavage of the last wafer by the Smart Cut technique. Effect of high temperature and hydrostatic pressure (HT–HP) treatment at temperatures up to 1570 K and pressure up to 1.2 GPa, typically for 5 h, on the SOI structures was investigated by Transmission Electron Microscopy, X-Ray and photoluminescence measurements. The point and extended defects are created at HT–HP, especially near the SOI surface. That effect depends on the SOI preparation method and treatment conditions and is related to the hydrogen and pressure assisted oxygen outdiffusion from SiO2 to the SOI surface and bulk. 2003 Elsevier Science Ltd. All rights reserved. Keywords: SOI; High temperature–pressure; Strain; Oxygen-related defect
1. Introduction Silicon on insulator (SOI) structures are produced in many ways. One of the most promising methods is an annealing of the bonded together Si wafers: one wafer with the surface SiO2 layer of about 0.5 µm thickness and the other one implanted with hydrogen atoms of appropriate dose and energy. Such processing results in a removal
∗
Corresponding author. Tel.: +48-22-5487792; fax +48-22-8470631. E-mail address: [email protected] (A. Misiuk).
1463-0184/02/$ - see front matter 2003 Elsevier Science Ltd. All rights reserved. doi:10.1016/S1463-0184(02)00024-2
156
A. Misiuk et al. / Crystal Engineering 5 (2002) 155–161
of excessive Si by its cleavage (Smart Cut technique) [1], while some part of implanted oxygen remains in the Si matrix. The Smart Cut cleavage is done at enhanced temperature (HT) and the near-surface (top) Si layer (typically of ⱕ 1 µm thickness) becomes strained during cooling. It is possible to tune the stress at the Si / buried SiO2 (BOX) layer / Si boundaries by annealing the SOI structure under enhanced hydrostatic pressure (HP) of inert gas ambient [2]. That approach has just been proven to deliver important information on the stress - induced phenomena in other kind of SOI, prepared by the separation by implanted oxygen (SIMOX) [3]. The main goal of the present work is an investigation of the effect of treatment under enhanced temperatures and pressures (HT–HP) on the SOI structures prepared by wafer bonding with the subsequent Smart Cut cleavage processing.
2. Experimental Two types of SOI samples (which we named A and B) were prepared by bonding and the Smart Cut technique in the following ways: A samples: as bonded (cleavage at 720 K): 0.48 µm thick 001 oriented Cz-Si-0.4 µm thick SiO2 - 0.4 mm thick Fz-Si (Cz-Si means Czochralski grown single crystalline silicon and Fz-Si—Floating zone grown single crystalline silicon). Temperature (T) of the wafer during hydrogen implantation was ⬍ 470 K. B samples: as bonded (cleavage at 720 K): 0.48 µm thick 111 oriented Fz-Si (0.3–0.48) µm thick SiO2 - 0.4 mm thick 001 oriented Cz - Si; T ⱕ 470 K.The SOI structures were subjected to the HT–HP treatment [4] for 5 h in Ar atmosphere at 1400, 1520 and 1570 K. The structure of the HT–HP treated SOI samples was examined by Transmission Electron Microscopy (TEM), X-Ray reciprocal space mapping (XRRSM) and photoluminescence (PL) measurements. PL measurements of the studied samples were performed in low temperature (10 K) with an Ar – ion laser (λ= 488 nm) used as an excitation source. The spectra were analysed in high resolution 0.55 m Jobin–Yvone monochromator (Triax 550) with liquid nitrogen cooled germanium detector.
3. Results and discussion The as prepared samples A and B indicate the presence of well defined buried SiO2 layer (BOX). The samples A subjected to the HT–HP treatment at HT = 1400 K under HP = 0.6 and 1. 1 GPa for 5 h indicate the presence of numerous dislocation loops in the near surface Si layer, at a distance of about 100 nm from the BOX layer (Fig. 1a). The treatment of the sample A at 1570 K - 1.23 GPa results in a dramatically worsened BOX structure. The BOX layer was transformed in part into polycrystalline like Si with still well defined top and bottom surfaces (Fig. 1b) and some dislocation loops, mostly in the near-surface Si layer. XRRSM’s of the samples A, as implanted and subjected to annealing (at 105 Pa)
A. Misiuk et al. / Crystal Engineering 5 (2002) 155–161
157
Fig. 1. TEM images of SOI samples. a: sample A treated at 1400 K - 1.1 GPa; b: sample A treated at 1570 K - 1.23 GPa; c: sample B treated at 1570 K - 1.23 GPa.
/ treatments at HT = 1400, 1520 and 1570 K for 5 h are presented in Fig. 2a–f. The annealing or treatment at 1400 K does not exert marked effect on X-Ray scattering pattern from the Si sample bulk (see left images). The HT–HP treatments at 1520– 1570 K - HP for 5 h result in dramatically increased X-Ray diffuse scattering (Fig. 2d–f). It is obviously related to an increased concentration of some defects in the Si bulk, which is, however, not detected in TEM measurements (compare Fig. 1b).
Fig. 2. Two dimensional XRRSMs recorded near 004 reciprocal space point of SOI samples A (patterns b–f: annealing / treatment for 5 h). a: as prepared; b: annealed at 1400 K - 105 Pa; c: treated at 1400 K - 1. 1 GPa; d: treated at 1520 K - 0.85 GPa; e: treated at 1570 K - 0.6 GPa; f - treated at 1570 K 1.2 GPa. The axes are marked in λ/2d units (λ- wavelength, d - interplanar distance). The left image corresponds to Si bulk while the right one—to the Si top near-surface layer.
158
A. Misiuk et al. / Crystal Engineering 5 (2002) 155–161
Annealing at 1400 K under atmospheric pressure results in the improved structural perfection of the surface Si layer (right images, compare Fig. 2a and b), even more pronounced at HP (compare Fig. 2b and c). That structural perfection is worsening with HP for the higher treatment temperatures, HT (Fig. 2d–f). The as prepared sample A indicates strong PL at energy equal about 1.1 eV, originating from the band to band transition. The same peak is seen in the PL spectrum of the sample annealed at 1400 K under atmospheric pressure of ambient (Fig. 3). The treatment at 1400 K - 0.6 / 1.2 GPa results in almost complete disappearance of that peak; also no peaks related to the presence of dislocations (D1–D5 peaks equal about, respectively, E = 0.80, 0.87, 0.93, 0.99 and 0.83 eV [5]) are detected. The treatments at 1570 K result in the same absence of distinct dislocation related PL. However, strong PL peaks at about 1.03 and 1.08 eV are seen in the PL spectrum of the sample A treated at 1570 K - 0.6 GPa (Fig. 3). The PL peak at 1.03 eV is probably related to the presence of interstitials or their clusters [6], while the origin of that at E = 1.08 eV is not known yet. The absence of the PL peak at E ⬇ 1.1 eV is obviously related to the non radiative recombination centres present in a high concentration. As detected by TEM and contrary to the case of samples A, the HT–HP treatment of the samples B at temperatures up to HT = 1570 K and pressure up to HP = 1.2 GPa exerted practically no effect on the BOX layers. Both their surfaces remained smooth and no defects were detected in the Si substrate and top layer (Fig. 1c). XRRSMs of the samples B treated at 1570 K – HP indicate the enhanced intensity
Fig. 3. PL spectra of SOI samples A, annealed / treated at 1400 and 1570 K. Treatment conditions indicated.
A. Misiuk et al. / Crystal Engineering 5 (2002) 155–161
159
of X-Ray diffuse scattering. Similarly as in the case of samples A, it can be interpreted as evidence of their worsened structural perfection. Also similar to the samples A, most samples B treated at 1570 K - HP indicate no PL peaks related to the band to band transition or dislocation related radiative recombination (Fig. 4). Only the sample B treated at the most severe conditions (HT = 1570 K and HP = 1.2 GPa) indicates the presence of very weak PL at E ⬇0.99 eV. This peak corresponds to the D4 dislocation-related line [5]. Still an absence of PL peaking at E ⬇ 1.1 eV confirms the presence of non radiative recombination centres at a high concentration, produced in effect of the HT–HP treatment. Both kinds of investigated SOI samples, A and B, indicate, after the HT–HP treatment, especially in the most severe conditions, substantial worsening of the structural perfection of the Si near-surface and deep (bulk) materials, evidenced e.g. by the XRRSM and PL data. In particular, the very low intensity or the absence of the PL peak at E ⬇ 1.1 eV (of high intensity for the as prepared SOI samples) confirms the strongly worsened structural perfection of the HT–HP treated SOI samples. That worsening is much more pronounced in the case of samples A, prepared in the same way as the samples B, but with one substantial difference: in a course of the sample A preparation the substrate temperature during hydrogen implantation was lower (T ⬍ 470 K) in comparison to that for the sample B (T ⱖ 470 K). Hydrogen implantation to the substrate follows, owing to high mobility of implanted H+ ions, in their diffusion towards the deeper part of the Si wafer, while those ions, implanted at comparatively high temperature, can create hydrogen-filled bubbles and cavities just at implantation [7]. It means that, after performing the
Fig. 4. cated.
PL spectra of SOI samples B treated at 1570 K under different HP. Treatment conditions indi-
160
A. Misiuk et al. / Crystal Engineering 5 (2002) 155–161
Smart Cut processing (typically at T ⱖ 720 K), more hydrogen is still present in the SOI samples prepared using hydrogen implantation into a cool Si wafer. During further processing (also at the Smart Cut stage) some of the hydrogen atoms are gettered at the BOX / Si interface (most just at the top interface), others are escaping the Si lattice. The presence of hydrogen results in strongly enhanced oxygen diffusivity [8,9], also at HT–HP [10]. Owing to this hydrogen and pressure stimulated diffusivity, some part of the oxygen from the BOX layer is migrating towards the sample surface and the SOI structure depth, creating, at sample cooling, small oxygen containing clusters. Because of their small size those clusters are not detected by TEM, but the PL and XRRSM data clearly confirm their presence. The samples A, prepared with hydrogen implantation into rather cool Si substrate, contained more hydrogen admixture, distributed mostly in the near surface Si layer and gettered mainly at the top BOX / Si boundary. During the HT–HP treatment, those hydrogen atoms in a comparatively high concentration, react with the SiO2 layer. It can result in dramatic worsening of the BOX layer perfection, especially after the treatments at (1520–1570) K - HP (Fig. 1b), as well as in the creation of oxide precipitates and dislocation loops in Si (Fig. 1a). The samples B, prepared with hydrogen implantation into the warmer Si substrate (T ⱖ 470 K), contain less hydrogen atoms. Their presence did not affect the integrity of the BOX layer (Fig. 1c). Still, at HT–HP, hydrogen atoms assisted in the HPstimulated outdiffusion of oxygen atoms towards the SOI structure surface and bulk also in the case of samples B. With releasing HT and HP to ambient conditions that oxygen atoms created (as in the case of samples A), small oxygen containing clusters. Those clusters were not detected by TEM but there is other evidence (lack of PL at E ⬇ 1.1 eV and the increased intensity of X-Ray diffuse scattering) of their creation. Our explanation of the observed effects in the HT–HP treated SOI samples still remains speculative so further investigation is needed to confirm the reason for the dramatic worsening of SOI structure perfection after its subjecting to annealing under enhanced hydrostatic pressure of ambient gas. Acknowledgements The authors thank Dr J. Jun from the High Pressure Research Centre PAS, Warsaw and Mr M. Prujszczyk from the Institute of Electron Technology, Warsaw for the HT–HP treatments. This work was supported by the Polish Committee for Scientific Research, grant no. 8T11B 072 19 at 2000 - 2002. References [1] X. Lu, N.W. Cheung, M.D. Strathman, P.K. Chu, B. Doyle, Appl. Phys. Lett 71 (1997) 1804. [2] J. Bak-Misiuk, I.V. Antonova, A. Misiuk, J. Domagala, V.P. Popov, V.I. Obodnikov, J. Hartwig, A. Romano-Rodriguez, A. Bachrouri, J. Alloys Comp 328 (2001) 181.
A. Misiuk et al. / Crystal Engineering 5 (2002) 155–161
161
[3] A. Misiuk, J. Bak-Misiuk, L. Bryja, J. Katcki, J. Ratajczak, J. Jun, B. Surma, Acta Phys. Polon A101 (2002) 719. [4] A. Misiuk, Mater. Phys. Mech 1 (2000) 119. [5] S. Pizzini, S. Binetti, M. Acciarri, M. Casati, Mat. Res. Soc. Symp. Proc 588 (2000) 117. [6] M. Nakamura, Jpn. J. Appl. Phys 40 (2001) L1000. [7] L.-J. Huang, Q.-Y. Tong, Y.-L. Chao, T.-H. Lee, T. Martini, U. Gosele, Appl. Phys. Lett 74 (1999) 982. [8] L. Zhong, F. Shimura, J. Appl. Phys 73 (1993) 707. [9] R. Job, A.G. Ulyashin, W.R. Fahrner, A.I. Ivanov, L. Palmetshofer, Appl. Phys. A 72 (2001) 326. [10] A. Misiuk, A. Barcz, V. Raineri, J. Ratajczak, J. Bak-Misiuk, I.V. Antonova, W. Wierzchowski, K. Wieteska, Physica B 308-310 (2001) 317.
Effect of high temperature - pressure on SOI structure A. Misiuk a,∗, L. Bryja b, J. Bak-Misiuk c, J. Ratajczak a, I.V. Antonova d, V.P. Popov d a Institute of Electron Technology, Al. Lotnikow 46, 02-668 Warsaw, Poland Wroclaw University of Technology, Wyb. Wyspianskiego 27, 50-370 Wroclaw, Poland c Institute of Physics, PAS, Al. Lotnikow 32/46, 02-668 Warsaw, Poland d Institute of Semiconductor Physics, RAS, Lavrentieva 13, 630090 Novosibirsk, Russia
b
Abstract Silicon on insulator (SOI) structures (Si / SiO2 layer / Si) were prepared by bonding the oxidised Si wafer with the hydrogen implanted one and a cleavage of the last wafer by the Smart Cut technique. Effect of high temperature and hydrostatic pressure (HT–HP) treatment at temperatures up to 1570 K and pressure up to 1.2 GPa, typically for 5 h, on the SOI structures was investigated by Transmission Electron Microscopy, X-Ray and photoluminescence measurements. The point and extended defects are created at HT–HP, especially near the SOI surface. That effect depends on the SOI preparation method and treatment conditions and is related to the hydrogen and pressure assisted oxygen outdiffusion from SiO2 to the SOI surface and bulk. 2003 Elsevier Science Ltd. All rights reserved. Keywords: SOI; High temperature–pressure; Strain; Oxygen-related defect
1. Introduction Silicon on insulator (SOI) structures are produced in many ways. One of the most promising methods is an annealing of the bonded together Si wafers: one wafer with the surface SiO2 layer of about 0.5 µm thickness and the other one implanted with hydrogen atoms of appropriate dose and energy. Such processing results in a removal
∗
Corresponding author. Tel.: +48-22-5487792; fax +48-22-8470631. E-mail address: [email protected] (A. Misiuk).
1463-0184/02/$ - see front matter 2003 Elsevier Science Ltd. All rights reserved. doi:10.1016/S1463-0184(02)00024-2
156
A. Misiuk et al. / Crystal Engineering 5 (2002) 155–161
of excessive Si by its cleavage (Smart Cut technique) [1], while some part of implanted oxygen remains in the Si matrix. The Smart Cut cleavage is done at enhanced temperature (HT) and the near-surface (top) Si layer (typically of ⱕ 1 µm thickness) becomes strained during cooling. It is possible to tune the stress at the Si / buried SiO2 (BOX) layer / Si boundaries by annealing the SOI structure under enhanced hydrostatic pressure (HP) of inert gas ambient [2]. That approach has just been proven to deliver important information on the stress - induced phenomena in other kind of SOI, prepared by the separation by implanted oxygen (SIMOX) [3]. The main goal of the present work is an investigation of the effect of treatment under enhanced temperatures and pressures (HT–HP) on the SOI structures prepared by wafer bonding with the subsequent Smart Cut cleavage processing.
2. Experimental Two types of SOI samples (which we named A and B) were prepared by bonding and the Smart Cut technique in the following ways: A samples: as bonded (cleavage at 720 K): 0.48 µm thick 001 oriented Cz-Si-0.4 µm thick SiO2 - 0.4 mm thick Fz-Si (Cz-Si means Czochralski grown single crystalline silicon and Fz-Si—Floating zone grown single crystalline silicon). Temperature (T) of the wafer during hydrogen implantation was ⬍ 470 K. B samples: as bonded (cleavage at 720 K): 0.48 µm thick 111 oriented Fz-Si (0.3–0.48) µm thick SiO2 - 0.4 mm thick 001 oriented Cz - Si; T ⱕ 470 K.The SOI structures were subjected to the HT–HP treatment [4] for 5 h in Ar atmosphere at 1400, 1520 and 1570 K. The structure of the HT–HP treated SOI samples was examined by Transmission Electron Microscopy (TEM), X-Ray reciprocal space mapping (XRRSM) and photoluminescence (PL) measurements. PL measurements of the studied samples were performed in low temperature (10 K) with an Ar – ion laser (λ= 488 nm) used as an excitation source. The spectra were analysed in high resolution 0.55 m Jobin–Yvone monochromator (Triax 550) with liquid nitrogen cooled germanium detector.
3. Results and discussion The as prepared samples A and B indicate the presence of well defined buried SiO2 layer (BOX). The samples A subjected to the HT–HP treatment at HT = 1400 K under HP = 0.6 and 1. 1 GPa for 5 h indicate the presence of numerous dislocation loops in the near surface Si layer, at a distance of about 100 nm from the BOX layer (Fig. 1a). The treatment of the sample A at 1570 K - 1.23 GPa results in a dramatically worsened BOX structure. The BOX layer was transformed in part into polycrystalline like Si with still well defined top and bottom surfaces (Fig. 1b) and some dislocation loops, mostly in the near-surface Si layer. XRRSM’s of the samples A, as implanted and subjected to annealing (at 105 Pa)
A. Misiuk et al. / Crystal Engineering 5 (2002) 155–161
157
Fig. 1. TEM images of SOI samples. a: sample A treated at 1400 K - 1.1 GPa; b: sample A treated at 1570 K - 1.23 GPa; c: sample B treated at 1570 K - 1.23 GPa.
/ treatments at HT = 1400, 1520 and 1570 K for 5 h are presented in Fig. 2a–f. The annealing or treatment at 1400 K does not exert marked effect on X-Ray scattering pattern from the Si sample bulk (see left images). The HT–HP treatments at 1520– 1570 K - HP for 5 h result in dramatically increased X-Ray diffuse scattering (Fig. 2d–f). It is obviously related to an increased concentration of some defects in the Si bulk, which is, however, not detected in TEM measurements (compare Fig. 1b).
Fig. 2. Two dimensional XRRSMs recorded near 004 reciprocal space point of SOI samples A (patterns b–f: annealing / treatment for 5 h). a: as prepared; b: annealed at 1400 K - 105 Pa; c: treated at 1400 K - 1. 1 GPa; d: treated at 1520 K - 0.85 GPa; e: treated at 1570 K - 0.6 GPa; f - treated at 1570 K 1.2 GPa. The axes are marked in λ/2d units (λ- wavelength, d - interplanar distance). The left image corresponds to Si bulk while the right one—to the Si top near-surface layer.
158
A. Misiuk et al. / Crystal Engineering 5 (2002) 155–161
Annealing at 1400 K under atmospheric pressure results in the improved structural perfection of the surface Si layer (right images, compare Fig. 2a and b), even more pronounced at HP (compare Fig. 2b and c). That structural perfection is worsening with HP for the higher treatment temperatures, HT (Fig. 2d–f). The as prepared sample A indicates strong PL at energy equal about 1.1 eV, originating from the band to band transition. The same peak is seen in the PL spectrum of the sample annealed at 1400 K under atmospheric pressure of ambient (Fig. 3). The treatment at 1400 K - 0.6 / 1.2 GPa results in almost complete disappearance of that peak; also no peaks related to the presence of dislocations (D1–D5 peaks equal about, respectively, E = 0.80, 0.87, 0.93, 0.99 and 0.83 eV [5]) are detected. The treatments at 1570 K result in the same absence of distinct dislocation related PL. However, strong PL peaks at about 1.03 and 1.08 eV are seen in the PL spectrum of the sample A treated at 1570 K - 0.6 GPa (Fig. 3). The PL peak at 1.03 eV is probably related to the presence of interstitials or their clusters [6], while the origin of that at E = 1.08 eV is not known yet. The absence of the PL peak at E ⬇ 1.1 eV is obviously related to the non radiative recombination centres present in a high concentration. As detected by TEM and contrary to the case of samples A, the HT–HP treatment of the samples B at temperatures up to HT = 1570 K and pressure up to HP = 1.2 GPa exerted practically no effect on the BOX layers. Both their surfaces remained smooth and no defects were detected in the Si substrate and top layer (Fig. 1c). XRRSMs of the samples B treated at 1570 K – HP indicate the enhanced intensity
Fig. 3. PL spectra of SOI samples A, annealed / treated at 1400 and 1570 K. Treatment conditions indicated.
A. Misiuk et al. / Crystal Engineering 5 (2002) 155–161
159
of X-Ray diffuse scattering. Similarly as in the case of samples A, it can be interpreted as evidence of their worsened structural perfection. Also similar to the samples A, most samples B treated at 1570 K - HP indicate no PL peaks related to the band to band transition or dislocation related radiative recombination (Fig. 4). Only the sample B treated at the most severe conditions (HT = 1570 K and HP = 1.2 GPa) indicates the presence of very weak PL at E ⬇0.99 eV. This peak corresponds to the D4 dislocation-related line [5]. Still an absence of PL peaking at E ⬇ 1.1 eV confirms the presence of non radiative recombination centres at a high concentration, produced in effect of the HT–HP treatment. Both kinds of investigated SOI samples, A and B, indicate, after the HT–HP treatment, especially in the most severe conditions, substantial worsening of the structural perfection of the Si near-surface and deep (bulk) materials, evidenced e.g. by the XRRSM and PL data. In particular, the very low intensity or the absence of the PL peak at E ⬇ 1.1 eV (of high intensity for the as prepared SOI samples) confirms the strongly worsened structural perfection of the HT–HP treated SOI samples. That worsening is much more pronounced in the case of samples A, prepared in the same way as the samples B, but with one substantial difference: in a course of the sample A preparation the substrate temperature during hydrogen implantation was lower (T ⬍ 470 K) in comparison to that for the sample B (T ⱖ 470 K). Hydrogen implantation to the substrate follows, owing to high mobility of implanted H+ ions, in their diffusion towards the deeper part of the Si wafer, while those ions, implanted at comparatively high temperature, can create hydrogen-filled bubbles and cavities just at implantation [7]. It means that, after performing the
Fig. 4. cated.
PL spectra of SOI samples B treated at 1570 K under different HP. Treatment conditions indi-
160
A. Misiuk et al. / Crystal Engineering 5 (2002) 155–161
Smart Cut processing (typically at T ⱖ 720 K), more hydrogen is still present in the SOI samples prepared using hydrogen implantation into a cool Si wafer. During further processing (also at the Smart Cut stage) some of the hydrogen atoms are gettered at the BOX / Si interface (most just at the top interface), others are escaping the Si lattice. The presence of hydrogen results in strongly enhanced oxygen diffusivity [8,9], also at HT–HP [10]. Owing to this hydrogen and pressure stimulated diffusivity, some part of the oxygen from the BOX layer is migrating towards the sample surface and the SOI structure depth, creating, at sample cooling, small oxygen containing clusters. Because of their small size those clusters are not detected by TEM, but the PL and XRRSM data clearly confirm their presence. The samples A, prepared with hydrogen implantation into rather cool Si substrate, contained more hydrogen admixture, distributed mostly in the near surface Si layer and gettered mainly at the top BOX / Si boundary. During the HT–HP treatment, those hydrogen atoms in a comparatively high concentration, react with the SiO2 layer. It can result in dramatic worsening of the BOX layer perfection, especially after the treatments at (1520–1570) K - HP (Fig. 1b), as well as in the creation of oxide precipitates and dislocation loops in Si (Fig. 1a). The samples B, prepared with hydrogen implantation into the warmer Si substrate (T ⱖ 470 K), contain less hydrogen atoms. Their presence did not affect the integrity of the BOX layer (Fig. 1c). Still, at HT–HP, hydrogen atoms assisted in the HPstimulated outdiffusion of oxygen atoms towards the SOI structure surface and bulk also in the case of samples B. With releasing HT and HP to ambient conditions that oxygen atoms created (as in the case of samples A), small oxygen containing clusters. Those clusters were not detected by TEM but there is other evidence (lack of PL at E ⬇ 1.1 eV and the increased intensity of X-Ray diffuse scattering) of their creation. Our explanation of the observed effects in the HT–HP treated SOI samples still remains speculative so further investigation is needed to confirm the reason for the dramatic worsening of SOI structure perfection after its subjecting to annealing under enhanced hydrostatic pressure of ambient gas. Acknowledgements The authors thank Dr J. Jun from the High Pressure Research Centre PAS, Warsaw and Mr M. Prujszczyk from the Institute of Electron Technology, Warsaw for the HT–HP treatments. This work was supported by the Polish Committee for Scientific Research, grant no. 8T11B 072 19 at 2000 - 2002. References [1] X. Lu, N.W. Cheung, M.D. Strathman, P.K. Chu, B. Doyle, Appl. Phys. Lett 71 (1997) 1804. [2] J. Bak-Misiuk, I.V. Antonova, A. Misiuk, J. Domagala, V.P. Popov, V.I. Obodnikov, J. Hartwig, A. Romano-Rodriguez, A. Bachrouri, J. Alloys Comp 328 (2001) 181.
A. Misiuk et al. / Crystal Engineering 5 (2002) 155–161
161
[3] A. Misiuk, J. Bak-Misiuk, L. Bryja, J. Katcki, J. Ratajczak, J. Jun, B. Surma, Acta Phys. Polon A101 (2002) 719. [4] A. Misiuk, Mater. Phys. Mech 1 (2000) 119. [5] S. Pizzini, S. Binetti, M. Acciarri, M. Casati, Mat. Res. Soc. Symp. Proc 588 (2000) 117. [6] M. Nakamura, Jpn. J. Appl. Phys 40 (2001) L1000. [7] L.-J. Huang, Q.-Y. Tong, Y.-L. Chao, T.-H. Lee, T. Martini, U. Gosele, Appl. Phys. Lett 74 (1999) 982. [8] L. Zhong, F. Shimura, J. Appl. Phys 73 (1993) 707. [9] R. Job, A.G. Ulyashin, W.R. Fahrner, A.I. Ivanov, L. Palmetshofer, Appl. Phys. A 72 (2001) 326. [10] A. Misiuk, A. Barcz, V. Raineri, J. Ratajczak, J. Bak-Misiuk, I.V. Antonova, W. Wierzchowski, K. Wieteska, Physica B 308-310 (2001) 317.