Electrical Characterization of Some Native Insulators on Germanium

Gregory, Otto J.; Crisman, E. E.; Pruitt, Lisa A.; Hymes, Diane; Rosenberg, J.J.

doi:10.1557/proc-76-307

Cited by 21 publications

(10 citation statements)

References 4 publications

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“…Unlike silicon, however, the lack of a sufficiently stable native oxide hinders the passivation of Ge surfaces. During the last four decades, dielectric materials like SiO [3], [4], SiO on a thin Si cap [2], [5], GeO [6], [7], Ge N [8], [9], Ge oxynitride [10], [11], and Al O [12], [13] have been attempted, although none of them would likely offer an EOT of less than 10 Å to advance beyond the sub-20 nm regime [1]. Inspired by the recent successes of the high-dielectric deposition technique on Si [14], [15] and the thermodynamically unstable nature of the common hexagonal phase of GeO , we have investigated the possibility of applying high-dielectrics to Ge without a native oxide interlayer.…”

Section: Introductionmentioning

confidence: 99%

Germanium MOS capacitors incorporating ultrathin high-/spl kappa/ gate dielectric

Chui

Ramanathan

Triplett

et al. 2002

IEEE Electron Device Lett.

337

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For the first time, we have successfully demonstrated the feasibility of integrating a high-permittivity ( ) gate dielectric material zirconium oxide into the MOS capacitors fabricated on pure germanium substrates. The entire fabrication process was essentially performed at room temperature with the exception of a 410 C forming gas anneal. After processing steps intended to remove the germanium native oxide interlayer between the zirconium oxide dielectric and germanium substrate, an excellent capacitance-based equivalent SiO 2 thickness (EOT) on the order of 5-8 Å and capacitance-voltage ( -) characteristics with hysteresis of 16 mV have been achieved. Additionally, excellent device yield and uniformity were possible using this low thermal budget process.

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Section: Introductionmentioning

confidence: 99%

Germanium MOS capacitors incorporating ultrathin high-/spl kappa/ gate dielectric

Chui

Ramanathan

Triplett

et al. 2002

IEEE Electron Device Lett.

337

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“…III-V compound semiconductors are used for fabrication of high speed electronic devices, integrated circuits, photonic devices such as light detectors, light-emitting diodes, and semiconductor lasers, as well as optoelectronic circuits encompassing both electronic and photonic devices monolithically integrated. Whereas wet chemical etching was the only means to "shape" these materials into devices, in recent years plasma etching techniques have played a larger and larger role in the fabrication techniques, mainly because more nearly vertical walled features have been required for making through-the-wafer vias (1, 2), laser end mirrors (3)(4)(5), waveguides (6), and waveguide mirrors (7,8). These enhanced vertical etching requirements were met primarily by reactive ion etching (9-13), reactive ion beam etching (14-16), and ion milling (17).…”

Section: Discussionmentioning

confidence: 99%

“…Whereas wet chemical etching was the only means to "shape" these materials into devices, in recent years plasma etching techniques have played a larger and larger role in the fabrication techniques, mainly because more nearly vertical walled features have been required for making through-the-wafer vias (1, 2), laser end mirrors (3)(4)(5), waveguides (6), and waveguide mirrors (7,8). These enhanced vertical etching requirements were met primarily by reactive ion etching (9-13), reactive ion beam etching (14-16), and ion milling (17).…”

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confidence: 99%

Native Oxides Formed on Single‐Crystal Germanium by Wet Chemical Reactions

Gregory

Pruitt

Crisman

et al. 1988

J. Electrochem. Soc.

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Lq tflABSTRACT The preparation of stable oxide films on single-crystal germanium surfaces by a room temperature "wet" chemical oxidation technique is described. Characterization by IR-transmission, eUipsometry, x-ray photoelectron spectroscopy, Rutherford backscattering, and electron microscopy show that such films are dense, uniform, and free of defects. The oxides are a mixture of two germanium dioxide phases both of which have a cristobalite atomic configuration. Unlike hexagonal germania, these films are stable in both water and hydrofluoric acid. They can be totally converted to the hexagonal dioxide phase by heat-treatment in either oxygen or nitrogen ambient at 600~ The growth kinetics, mechanisms and morphologies of the oxides formed by this method are presented. Preliminary evaluation of the electronic character of the oxide/semiconductor interface is also included.The formation of native insulators on semiconductor surfaces is an essential part of the current technology in planar device fabrication. Dioxide and nitride films are readily grown on silicon surfaces by direct thermal reaction with gases. Other semiconductors, such as germanium, do not readily react with atmospheric pressure gases to form layers of "native" insulators. Germanium dioxide (hexagonal or amorphous) films prepared in this manner decompose at or near the formation temperature (1, 2) and are extremely soluble in water and other chemicals typically employed in IC processing. Thermally produced germanium nitrides tend to reach a stable equilibrium at thicknesses <250A (3) which is too thin for many applications.A number of device applications [CCD imaging arrays (4), monolithic electro-optic IC's (5), and others] are presently being evaluated which utilize particular properties of germanium. This has generated a renewed interest in establishing techniques for the formation of stable insulators on Ge that are passivating and/or suitable as diffusion barriers. To date the most promising method of forming passivating "native" insulators on germanium has been dry, high pressure (140 atm < P < 1400 atm), thermal oxidation followed by capping with an evaporated SiO2 layer (4, 6) or by nitriding in flowing NH3 (7, 8). The second step is necessary to prevent the oxides from deteriorating in the presence of atmospheric moisture. In an attempt to produce stable films at even lower temperatures than those (450 ~ 550~ used for high pressure oxidation (HPO), wet chemical oxidation (WCO) has been investigated. It is known from previous studies that certain WCO techniques produce oxides that are stable in both water and HF. Also, wet chemical reactions produce oxides at or below room temperature that are relatively thick (>1000A), generally of uniform thickness and free from imperfections.Specific references and observations concerning the various WCO techniques can be found in Ref. (8) which also includes a summary of the physical, electrical, and optical properties that were reported in earlier work. While some ambiguity exists in the identificat...

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“…By using this method, the resulting film thickness can be scaled down to an effective oxide thickness (EOT) as thin as 1.9 nm with acceptable leakage; the refractive index is found to be about 1.3-1.5 [6]. GeO x N y has better thermal and chemical stability than native Ge oxides (GeO and GeO 2 ) [7,8]. In addition, the incorporation of nitrogen into Ge oxides could reduce the potential interdiffusion between the gate dielectric and substrate and/or the gate electrode.…”

Section: Gate Stackmentioning

confidence: 99%