Surface passivation of the Ge substrate by novel nitrogen plasma immersion treatment

Lin, Meng; Li, Ming; An, Xia; Yun, Quanxin; Li, Min; Li, Zhiqiang; Liu, Pengqiang; Zhang, Xing; Huang, Ru

doi:10.1088/0268-1242/28/8/085010

Cited by 9 publications

(5 citation statements)

References 15 publications

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“…SiGe waveguide needs to be performed for less optical loss [15]. Although several Ge surface finishing methods based on wet etching and plasma techniques have been reported [18,19], the emphases have been placed only on applications in electronic devices, and the capacitance vs. voltage (C-V) curves are the main indices in those cases without studies of the changes in the optical properties of the Ge surface. On the other hand, RTA processing would be a faster, more reproducible and more cost-effective solution for a Ge surface treatment.…”

Section: Resultsmentioning

confidence: 99%

Surface Treatment of Ge Grown Epitaxially on Si by Ex-Situ Annealing for Optical Computing by Ge Technology

Chen¹,

Huo²,

Cho³

et al. 2014

IEIE Transactions on Smart Processing and Computing

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Abstract:Ge is becoming an increasingly popular semiconductor material with high Si compatibility for on-chip optical interconnect technology. For a better manifestation of the meritorious material properties of Ge, its surface treatment should be performed satisfactorily before the electronic and photonic components are fabricated. Ex-situ rapid thermal annealing (RTA) processes with different gases were carried out to examine the effects of the annealing gases on the thin-film quality of Ge grown epitaxially on Si substrates. The Ge-on-Si samples were prepared in different structures using the same equipment, reduced-pressure chemical vapor deposition (RPCVD), and the samples annealed in N 2 , forming gas (FG), and O 2 were compared with the unannealed (deposited and only cleaned) samples to confirm the improvements in Ge quality. To evaluate the thin-film quality, room-temperature photoluminescence (PL) measurements were performed. Among the compared samples, the O 2 -annealed samples showed the strongest PL signals, regardless of the sample structures, which shows that ex-situ RTA in the O 2 environment would be an effective technique for the surface treatment of Ge in fabricating Ge devices for optical computing systems.

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Section: Resultsmentioning

confidence: 99%

Surface Treatment of Ge Grown Epitaxially on Si by Ex-Situ Annealing for Optical Computing by Ge Technology

Chen¹,

Huo²,

Cho³

et al. 2014

IEIE Transactions on Smart Processing and Computing

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“…SiO 2 formed by oxidation of a Si cap layer was also proposed [8], unfortunately, the interface characteristics strongly depend on the exact thickness of the Si cap and the oxidation condition which implies that rigorous process control is required. In addition, nitridebased passivation and sulfur-based passivation layer such as GeN x [9], Hf 3 N 4 [10], AlN [10], GeS x [11], and H 2 S [12] were studied in the literature. However, a D it value close to or higher than 1.0 × 10 12 cm −2 eV −1 is obtained which is not desirable for device operation.…”

Section: Introductionmentioning

confidence: 99%

Surface Passivation of Ge MOS Devices by ${\rm SmGeO}_{\bf{x}}$ With Sub-nm EOT

Lin

et al. 2014

IEEE Electron Device Lett.

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Ge MOS devices passivated by SmGeO x with equivalent oxide thickness of 0.61 nm were employed as the platform to evaluate the eligibility of SmGeO x as Ge surface passivation layer. The SmGeO x layer was formed by deposition of Sm 2 O 3 on Ge substrate with a subsequent O 2 annealing and the formation of SmGeO x was confirmed by X-ray photoelectron spectroscopy. The tiny frequency dispersion in capacitance measurement and a low interface trap density of 5.1 × 10 11 cm −2 eV −1 near midgap attest to desirable passivation effect and it can be ascribed to Sm-Ge-O bonding, which is favorable in mitigating dangling bonds at Ge surface. In addition, the small hysteresis in capacitance also suggests good quality of bulk dielectric. Due to the small amount of bulk traps and large conduction band offset with respect to Ge, it enjoys low leakage current of 0.36 A/cm 2 at gate bias of V fb (flatband voltage)-1 V. Through the test of bias temperature instability, the passivation layer demonstrates reasonable reliability performance in terms of 65-mV flatband voltage shift at 85°C after stressing with −16 MV/cm for 1000 s. With these characteristics, SmGeO x is promising as a passivation layer for aggressively scaled Ge MOS devices.Index Terms-Ge surface passivation, SmGeO x , EOT, interface trap density, leakage current, bias temperature instability.

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“…Nitrogen and GeO 2 passivation have been proven to be effective methods. Nitrogen passivation can be achieved by NH 3 annealing and nitrogen plasma treatment (6,7). GeO 2 has been reported to be grown by an O 2 thermal treatment, ozone oxidation and O 2 plasma oxidation (8)(9)(10)(11)(12).…”

Section: Introductionmentioning

confidence: 99%

Investigation of Passivation of Ge Substrate by N₂O Plasma and N₂plasma Treatment

Lin

et al. 2014

ECS Trans.

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In this paper, passivation of Ge substrate by N2O plasma is proposed and compared with N2 plasma treatment. Results show that both N2O and N2 plasma treatment can improve the quality of the interface between high K dielectric and Ge substrate and the CV characteristics of MOS capacitors. Results show that, stoichiometric GeO2 is achieved by N2O plasma oxidation and GeOxNy is formed by N2 plasma treatment, due to native oxide residue or oxidation after aqueous cleaning. Comparing to GeOxNy passivation, GeO2 passivation is superior in reducing interface state density to ~2×1011cm-2eV-1, suppressing EOT degradation and modulating the surface potential, which is promising for high performance Ge NMOSFETs fabrication.

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Surface passivation of the Ge substrate by novel nitrogen plasma immersion treatment

Cited by 9 publications

References 15 publications

Surface Treatment of Ge Grown Epitaxially on Si by Ex-Situ Annealing for Optical Computing by Ge Technology

Surface Treatment of Ge Grown Epitaxially on Si by Ex-Situ Annealing for Optical Computing by Ge Technology

Surface Passivation of Ge MOS Devices by ${\rm SmGeO}_{\bf{x}}$ With Sub-nm EOT

Investigation of Passivation of Ge Substrate by N₂O Plasma and N₂plasma Treatment

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Surface passivation of the Ge substrate by novel nitrogen plasma immersion treatment

Cited by 9 publications

References 15 publications

Surface Treatment of Ge Grown Epitaxially on Si by Ex-Situ Annealing for Optical Computing by Ge Technology

Surface Treatment of Ge Grown Epitaxially on Si by Ex-Situ Annealing for Optical Computing by Ge Technology

Surface Passivation of Ge MOS Devices by ${\rm SmGeO}_{\bf{x}}$ With Sub-nm EOT

Investigation of Passivation of Ge Substrate by N2O Plasma and N2 plasma Treatment

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Investigation of Passivation of Ge Substrate by N₂O Plasma and N₂plasma Treatment