Process for selectively depositing diamond films

#1. Field of the Invention

#The present invention generally relates to a process for selectively depositing diamond films, more particularly to a process for selectively depositing diamond films with the gas source of a mixture of C.sub.x H.sub.y plus CO.sub.2 or C.sub.x H.sub.y O.sub.z plus CO.sub.2. The present process include two stages of diamond deposition. In the period between the first and second stage, the substrate is immersed in an aqueous solution of HF plus HNO.sub.3 to increase the selectivity of diamond growth.

#2. Description of the Prior Art

#FIGS. 1A through 1D are schematic cross-sectional views depicting the process of selectively depositing diamond films of the present invention.

#FIG. 2A is a SEM image of the surface of the diamond films obtained from Example 1.

#FIG. 2B is a SEM image of the surface of the diamond films obtained from Example 2.

#FIGS. 1A through 1D are schematic cross-sectional views depicting the process of selectively depositing diamond films of the present invention. Referring first to FIG. 1A, an etch-resistant layer 11 is formed on a cleaned silicon substrate 10 with a predetermined pattern through the use of ordinary photolithographic masking techniques. The etch-resistant layer can be a positive photoresist, a negative photoresist or silicon dioxide.

#Next, the silicon substrate is roughened to form diamond nucleation sites, which can be achieved by immersing the substrate into diamond powders-containing water with ultrasonic agitation or by an ion implantation step. Since the etch-resistant layer can serve as a masking layer, by either of the above steps, different diamond nucleation density on the substrate will result, that is, the diamond nucleation density on the region uncovered by the etch-resistant layer is substantially greater than that on the region covered by the etch-resistant layer by several orders. Accordingly, in the subsequent deposition, diamond can be grown in a selective way, that is, more diamond particles will be deposited on the uncovered region of the substrate than on the covered region of the substrate.

#The term "covered region" or "undesired region" hereinafter refers to the region of the substrate covered by the etch-resistant layer after the etch-resistant layer has been patterned. The term "uncovered region" or "exposed region" hereinafter refers to the region of the substrate uncovered by the etch-resistant layer after the etch-resistant layer has been patterned.