Claims
- 1. A process for uniform nucleation on a growth substrate using at least one of diamond and a diamond-like carbon from a gaseous phase, comprising:
- (a) pretreating the substrate,
- (b) arranging the substrate in a reactor, and
- (c) applying a bias voltage in the form of an alternating voltage to the substrate and supplying gases to the growth substrate,
- wherein a frequency of between 0.5 and 500 Hz is the frequency for the bias voltage and its negative peak voltage is less than -30 V, and within a period, the bias voltage is applied during an active time (t.sub.on) with a value of less than -30 V, and within the period, the bias voltage for a currentless time (t.sub.off) in an interval is higher than 30 V.
- 2. The process according to claim 1, wherein the bias voltage in the currentless time (t.sub.off) is between -30 V and +30 V.
- 3. The process according to claim 1, wherein the frequency is between 1 and 100 Hz.
- 4. The process according to claim 1, wherein the frequency is between 1 and 10 Hz.
- 5. The process according to claim 1, wherein, within a period, the bias voltage for an active time (t.sub.on) is applied at a value lower than -30 V, and within the period, the bias voltage is applied for a currentless time (t.sub.off) in an interval within .+-.30 v, and the active time (t.sub.on) is adjusted to be approximately as long as the currentless time (t.sub.off).
- 6. The process according to claim 1, wherein within a period, the bias voltage for a defined active time (t.sub.on) is applied at a value lower than -30 V, and within the period, the bias voltage is applied for a currentless time (t.sub.off) in an interval within .+-.30 v, the sum of the active and the currentless time being selected as a period duration of the period.
- 7. The process according to claim 1, wherein the bias voltage is applied within a period in each case for a certain time (t.sub.on) and is switched off for a certain time (t.sub.off).
- 8. The process according to claim 1, wherein a growth substrate made of silicon is selected.
- 9. The process according to claim 1, wherein a growth substrate made of .beta. silicon carbide (.beta.-SiC) is selected.
- 10. The process according to claim 1 occurring by plasma chemical vapor deposition (CVD).
- 11. The process according to claim 4 employing a frequency of approximately 5 Hz.
- 12. The process according to claim 1, wherein the bias voltage and its negative peak voltage is less than -50 v.
- 13. The process according to claim 1, wherein said gases comprise H.sub.2, CH.sub.4, N.sub.2 and O.sub.2.
- 14. A process for forming a diamond or a diamond-like carbon layer on a growth substrate, comprising:
- (a) pretreating the substrate,
- (b) arranging the substrate in a reactor, and
- (c) applying a bias voltage in the form of an alternating voltage to the substrate and supplying gases to the growth substrate,
- wherein a frequency of between 0.5 and 500 Hz is the frequency for the bias voltage and its negative peak voltage is less than -30 V, and within a period, the bias voltage is applied during a active time (t.sub.on) with a value of less than -30 V, and within the period, the bias voltage for a currentless time (t.sub.off) in an interval is higher than 30 V;
- forming diamond or a diamond-like carbon nuclei on a surface of the growth substrate; and
- forming the diamond or the diamond-like carbon layer on the surface of the growth substrate.
- 15. The process according to claim 14, wherein said forming of the diamond or diamond-like carbon layer is according to a growth rate defined as ##EQU2## wherein .alpha. is between 2 and 3, and wherein V.sub.100 is a growth rate in the <100> direction, and V.sub.111 is a growth rate in the <111> direction, wherein the <100> and <111> directions are according to Miller's indices for crystallography.
- 16. The process according to claim 14, wherein said gases comprise H.sub.2, CH.sub.4, N.sub.2 and O.sub.2.
Priority Claims (1)
Number |
Date |
Country |
Kind |
197 02 311 |
Jan 1997 |
DEX |
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Parent Case Info
This application claims priority from U.S. Provisional Application Ser. No. 60/037,950, filed on Feb. 20, 1997.
US Referenced Citations (9)
Foreign Referenced Citations (1)
Number |
Date |
Country |
WO 9408076 |
Apr 1994 |
WOX |
Non-Patent Literature Citations (2)
Entry |
S. Yugo et al., "Generation of diamondd nuclei by electric field im plasma chemical vapor deposition", Appl. Phys. Lett. 58 (10) pp. 1036-1038 Mar. 1991. |
Appl. Phys. Lett., vol. 68, No. 25, Jun. 17, 1996, pp. 3558-3560, entitled "Nucleation of High Oriented Diamond on Silicon via an Alternating Current Substrate Bias" by Wolter, et al.. |