Evidence of the role of positive bias in diamond growth by hot filament chemical vapor deposition

Cui, Jingbiao; Fang, Rongchuan

doi:10.1063/1.117227

Cited by 31 publications

(6 citation statements)

References 19 publications

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“…[45][46][47] In contrast, the application of negative bias voltage is efficient in reducing the size of the diamond grains. [21][22][23][24][25][26] The application of negative bias voltage in CH 4 / H 2 plasma attracts the positively charged species, such as H þ , CH 3 þ , CH þ and expels the electrons that markedly alter the plasma chemistry near the substrates.…”

Section: Discussionmentioning

confidence: 89%

Origin of graphitic filaments on improving the electron field emission properties of negative bias-enhanced grown ultrananocrystalline diamond films in CH4/Ar plasma

Sankaran

Huang

Saravanan

et al. 2014

Journal of Applied Physics

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Microstructural evolution of bias-enhanced grown (BEG) ultrananocrystalline diamond (UNCD) films has been investigated using microwave plasma enhanced chemical vapor deposition in gas mixtures of CH4 and Ar under different negative bias voltages ranging from −50 to −200 V. Scanning electron microscopy and Raman spectroscopy were used to characterize the morphology, growth rate, and chemical bonding of the synthesized films. Transmission electron microscopic investigation reveals that the application of bias voltage induced the formation of the nanographitic filaments in the grain boundaries of the films, in addition to the reduction of the size of diamond grains to ultra-nanosized granular structured grains. For BEG-UNCD films under −200 V, the electron field emission (EFE) process can be turned on at a field as small as 4.08 V/μm, attaining a EFE current density as large as 3.19 mA/cm2 at an applied field of 8.64 V/μm. But the films grown without bias (0 V) have mostly amorphous carbon phases in the grain boundaries, possessing poorer EFE than those of the films grown using bias. Consequently, the induction of nanographitic filaments in grain boundaries of UNCD films grown in CH4/Ar plasma due to large applied bias voltage of −200 V is the prime factor, which possibly forms interconnected paths for facilitating the transport of electrons that markedly enhance the EFE properties.

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Section: Discussionmentioning

confidence: 89%

Origin of graphitic filaments on improving the electron field emission properties of negative bias-enhanced grown ultrananocrystalline diamond films in CH4/Ar plasma

Sankaran

Huang

Saravanan

et al. 2014

Journal of Applied Physics

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“…33 It has been proposed that the influence of positive bias voltage on diamond growth is caused by the bombardment of electrons and/or negative charged ions on the surface of the substrate. 34 However, the abundance of the negatively charged species is about four orders of magnitude less than that of the eletrons. 35 Thus, their effect on modifying the growth of diamond can be ruled out.…”

Section: Discussionmentioning

confidence: 99%

Structural modification of nanocrystalline diamond films via positive/negative bias enhanced nucleation and growth processes for improving their electron field emission properties

Saravanan

Huang

Sankaran

et al. 2015

Journal of Applied Physics

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Electron field emission (EFE) properties of nanocrystalline diamond (NCD) films synthesized by the bias-enhanced growth (beg) process under different bias voltages were investigated. The induction of the nanographitic phases is presumed to be the prime factor in enhancing the EFE properties of negative biased NCD films. Transmission electron microscopic investigations reveal that a negative bias voltage of −300 V increases the rate of growth for NCD films with the size of the grains changing from nano to ultranano size. This effect also is accompanied by the induction of nanographitic filaments in the grain boundaries of the films. The turn-on field (E0) for the EFE process then effectively gets reduced. The EFE process of the beg-NCD−300V films can be turned on at E0 = 3.86 V/μm, and the EFE current density achieved is 1.49 mA/cm2 at an applied field of 7.85 V/μm. On the other hand, though a positive-bias beg process (+200 V) results in the reduction of grain size, it does not induce sufficient nanographitic phases to lower the E0 value of the EFE process. Moreover, the optical emission spectroscopic investigation indicates that one of the primary causes that changes the granular structure of the NCD films is the increase in the proportion of C2 and CH species induced in the growing plasma. The polarity of the bias voltage is of less importance in the microstructural evolution of the films.

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“…Ion impinging of the substrate surface can increase the surface mobility of absorbed species (Stoner et al , 1992), adatom diffusion (Jiang et al , 1994) or initialize the formation of the transient interlayer (Robertson et al , 1995). Generally, no signifi cant change to the gas species was observed by Cui and Fang (Cui and Fang, 1996). Yugo et al proposed that the hydrogen-enriched amorphous carbon layer could stabilize the diamond nuclei (Yugo et al , 1991).…”

Section: Double Biasingmentioning

confidence: 95%

Diamond nucleation and seeding techniques for tissue regeneration

Kromka

Babchenko

Potocký

et al. 2013

Diamond-Based Materials for Biomedical Applications

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Evidence of the role of positive bias in diamond growth by hot filament chemical vapor deposition

Cited by 31 publications

References 19 publications

Origin of graphitic filaments on improving the electron field emission properties of negative bias-enhanced grown ultrananocrystalline diamond films in CH4/Ar plasma

Origin of graphitic filaments on improving the electron field emission properties of negative bias-enhanced grown ultrananocrystalline diamond films in CH4/Ar plasma

Structural modification of nanocrystalline diamond films via positive/negative bias enhanced nucleation and growth processes for improving their electron field emission properties

Diamond nucleation and seeding techniques for tissue regeneration

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