Infrared absorption in silicon from shallow thermal donors incorporating hydrogen and a link to the NL10 paramagnetic resonance spectrum

Newman, R.C.; Tucker, James H. R.; Semaltianos, N. G.; Lightowlers, E C; Gregorkiewicz, T.; Zevenbergen, I.S.; Ammerlaan, C.A.J.

doi:10.1103/physrevb.54.r6803

Cited by 53 publications

(44 citation statements)

References 29 publications

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“…Instead, hydrogen-related shallow thermal donors ͑STDs͒ could easily be formed under such conditions. [30][31][32][33] This is further confirmed by the observation that after a direct plasma treatment of p-type CZ material, a p-n junction is observed by SRP, demonstrating the partial conversion to n-type material by the created STDs. 28,29 Origin of the near surface carrier and OTD profiles.-An important issue to be resolved is the origin of the carrier profiles in Fig.…”

Section: Discussionsupporting

confidence: 85%

Impact of Direct Plasma Hydrogenation on Thermal Donor Formation in n-Type CZ Silicon

Rafı́

Simoen

Claeys

et al. 2005

J. Electrochem. Soc.

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In this paper, the role of a direct plasma hydrogenation treatment and a subsequent air annealing at 450°C in the formation of thermal donors ͑TDs͒ in n-type Czochralski ͑CZ͒ silicon is investigated by means of a combination of capacitance-voltage ͑C-V͒ and deep-level transient spectroscopy ͑DLTS͒. The hydrogenation treatment is found to enhance the introduction rate of TDs at 450°C for shorter annealing times, reaching its maximum acceleration after 5 h and for the longest plasma hydrogenation studied ͑2 h͒. For much longer annealing times, the TD introduction rate becomes independent of the presence of hydrogen in the material. DLTS detects only one donor level having an activation energy, which lowers with increasing doping density of the material, from 0.106 to 0.093 eV. After activation energy correction for the Poole-Frenkel electric-field-enhanced emission, this trap is found to fit well with the conventional singly ionized oxygen thermal donor level. However, from C-V free carrier and DLTS trap concentrations, it is derived that other shallower donors, created by the plasma hydrogenation and 450°C anneal should play an important role in the free carrier concentration increase of the n-CZ silicon.By now, it is a well-accepted fact that hydrogen plays a catalytic role in the formation of thermal donors in Czochralski ͑CZ͒ silicon. 1-4 Hydrogen can be introduced in several ways in the material, among which a hydrogen plasma treatment is of strong interest due to its low cost, high throughput, and low thermal budget. 5 Combining a low-temperature plasma hydrogenation, followed by a relatively short thermal donor anneal at 450°C, it has been demonstrated that p-type starting material can be converted into n-type silicon, and therefore, deep p-n junctions can be obtained in a fast and cheap way. 5,6 The depth of the junction is thereby controlled by the hydrogen in-diffusion profile. 6 So far, most of our studies have focused on p-type CZ starting material. 5,6 In this paper, the impact of the plasma hydrogenation time on the thermal donor ͑TD͒ formation during annealing at 450°C from 30 min up to 50 h in n-type CZ material is investigated. It is shown by capacitance-voltage ͑C-V͒ doping profiles that there is indeed an enhancement of the TD formation rate for annealing times t a450 р 5 h. The maximum effect is observed after a 5 h anneal and increases with increasing plasma hydrogenation time t H , i.e., with the total amount of hydrogen in the material. For longer t a450 , the hydrogen impact diminishes, resulting in a final free electron introduction rate from C-V of about 1.7-1.8 ϫ 10 14 cm Ϫ3 /h for the n-type CZ silicon studied. In order to identify the created donors, deep level transient spectroscopy ͑DLTS͒ was performed on a selected group of samples. The resulting spectra are dominated by a donor level at an energy of 0.093-0.106 eV below the conduction band E C , shifting to lower values for increasing n-type doping density. By taking into account the Poole-Frenkel barrier lowering with increasing el...

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Section: Discussionsupporting

confidence: 85%

Impact of Direct Plasma Hydrogenation on Thermal Donor Formation in n-Type CZ Silicon

Rafı́

Simoen

Claeys

et al. 2005

J. Electrochem. Soc.

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“…There is no positive evidence that nitrogen is present in the STD(X)N centers but there is evidence that a lattice vacancy may be incorporated. Ultra-shallow donors, not discussed here, have been observed [4] and attributed to the presence of carbon, although there is no spectroscopic evidence to support this interpretation. It is clear that the problems of understanding TDDN and STNN centers in Si are still only partially resolved.…”

Section: Introduction Clustering Of Grown-in Interstitial Oxygen Atomentioning

confidence: 64%

“…No doubt this is the reason why the IR spectrum reported in [23] and attributed to nitrogen related donors prior to this analysis is, in fact, identical with the STD(H)N spectrum. It is important to recall that STD(H)N centers are not stable at 550 C [4] whereas STD(X)N centers increase their concentration at this temperature compared with anneals at 450 C. There is no direct evidence to identify X as a nitrogen atom and it is now proposed that X may only perturb and stabilize STD(H)N centers. In-diffusion of nitrogen could have occurred in our deuterated samples during the anneal in air at %550 C (following 2 MeV electron irradiation, Fig.…”

Section: Introduction Clustering Of Grown-in Interstitial Oxygen Atomentioning

confidence: 95%

“…The TDDN + centers also give rise to the electron paramagnetic resonance (EPR) NL8 spectrum and recent measurements demonstrate that adjacent members of the family have C 2v (orthorhombic) and monoclinic-I symmetries, respectively, as N increases [2,3]. Electron nuclear double resonance (ENDOR) measurements reveal the incorporation of Si atoms ( 29 Si, I = 2 ) but no other impurities (see [4] for a recent overview).…”

Section: Introduction Clustering Of Grown-in Interstitial Oxygen Atomentioning

confidence: 96%

“…No (IR) evidence for the incorporation of hydrogen in STD(X)N centers was obtained by replacing H by D, but ENDOR measurements have revealed its presence [24] in nitridated samples (heated in nitro- Stronger lines in co-nitridated and deuterated samples annealed at 550 C compared to co-nitridated and hydrogenated samples gen gas at 1300 C) and irradiated deuterated samples as well as in samples doped with nitrogen during crystal growth. We suggest that the X-defect could involve vacancies [4] that diffuse into Si from a surface layer of Si 3 N 4 up to a concentration of %10 14 cm ± ±3 during the nitridation treatment [25]. Irradiation damage is an alternative source of vacancies so that a subsequent 550 C anneal could again lead to STD(X)N formation in H-doped Si.…”

Section: Introduction Clustering Of Grown-in Interstitial Oxygen Atomentioning

confidence: 97%

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Shallow Thermal Donors in Silicon: The Roles of Al, H, N, and Point Defects

Newman

Ashwin

Pritchard

et al. 1998

phys. stat. sol. (b)

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Three families of shallow thermal donors have been identified in annealed Czochralski silicon from measurements of their infrared electronic transitions using Fourier transform spectroscopy. Donors produced in Al-doped Si incorporate an Al impurity; centers produced in hydrogenated material contain an H (or D) atom; a third set of donors labeled STD(X)N produced in nitridated or irradiated pre-hydrogenated samples may incorporate a lattice vacancy rather than a nitrogen atom. A critical review of the literature is made and some rationalization has been effected. Comments are included about the formation of donor centers following anneals of heavily damaged float-zone Si that also contains hydrogen.Introduction. Clustering of grown-in interstitial oxygen atoms (O i ) in Czochralski (Cz) Si annealed in the range 350 C T 500 C leads to the formation of a family of 16 or more different helium-like double donors (TDDN) that evolves with increasing annealing time (increasing N). TDDN 0 and TDDN + give rise to infrared (IR) electronic absorption lines in the ranges 350 to 533 cm ± ±1 and 580 to 1170 cm ± ±1 , respectively. The ionization energies E i of the individual TDDN 0 members decrease with a ªstaircaseº structure as N increases [1], implying that the structures of alternate members may differ slightly. The TDDN + centers also give rise to the electron paramagnetic resonance (EPR) NL8 spectrum and recent measurements demonstrate that adjacent members of the family have C 2v (orthorhombic) and monoclinic-I symmetries, respectively, as N increases [2,3]. Electron nuclear double resonance (ENDOR) measurements reveal the incorporation of Si atoms ( 29 Si, I =

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EPR Study of Hydrogen-Related Radiation-Induced Shallow Donors in Silicon

Маркевич

Mchedlidze

Suezawa

et al. 1998

phys. stat. sol. (b)

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An electron paramagnetic resonance (EPR) study of hydrogen-related radiation-induced shallow donors in silicon has been performed. Three species of this donor family (D1±D3) were observed earlier by means of infrared absorption measurements in hydrogenated Czochralski-grown Si (Cz-Si) crystals after irradiation with fast electrons and subsequent annealing in the temperature range of 300 to 550 C. An EPR signal with isotropic g-factor of 1.9987, labeled TU1, has been found in hydrogenated Cz-Si crystals which were irradiated and annealed at 300 to 350 C. It was shown that the TU1 signal is related to the shallow donor state of the D1 center. Annealing at temperatures higher than 350 C resulted in transformation of the D1 to the D2 centers. This led to the transformation of the TU1 spectrum to another one with S 1/2 and anisotropic g-tensor, the principal values of which were found to be very close to those for the Si-NL10 EPR spectra in silicon. The observed EPR spectra are compared with the Si-NL10 ones and possible atomic structures, and formation mechanisms of the defects which give rise to these spectra are discussed.

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Infrared absorption in silicon from shallow thermal donors incorporating hydrogen and a link to the NL10 paramagnetic resonance spectrum

Cited by 53 publications

References 29 publications

Impact of Direct Plasma Hydrogenation on Thermal Donor Formation in n-Type CZ Silicon

Impact of Direct Plasma Hydrogenation on Thermal Donor Formation in n-Type CZ Silicon

Shallow Thermal Donors in Silicon: The Roles of Al, H, N, and Point Defects

EPR Study of Hydrogen-Related Radiation-Induced Shallow Donors in Silicon

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