Resolution, masking capability and throughput for direct-write, ion implant mask patterning of diamond surfaces using ion beam lithography

Abstract

Direct-write, ion implant top surface imaging is a two-step nanopatterning method that simplifies and improves processing of diamond for various applications. The technique utilizes a low-dose (non-milling) gallium ion implant into the first few nanometers of the surface using a focused ion beam. The implanted regions form a hard mask to plasma etching allowing production of well-controlled high relief structures over the exposed surface. We demonstrate the ability of the process to fabricate high aspect ratio, high-resolution patterns over millimetre-size areas in all varieties of diamond including natural, synthetic HPHT and CVD films, at various levels of doping, for industrial scale applications. This paper sets significant new limits of resolution and masking capability for the technique, and compares throughput in comparison to other high resolution lithographic techniques.

Rapid Prototyping of Fresnel Zone Plates via Direct Ga+ Ion Beam Lithography for High-Resolution X-ray Imaging

“…With this new and improved fabrication scheme the preparation time of IBLÀFZPs in relation to the surface area, height, and comparable IBL parameters was reduced by a factor of 3.1 to 73.7, implying a significant reduction of costs while at the same time the first-order resolution was improved by a factor of 2. 39,48À50 Exciting enough, the results were obtained not with state of the art IBL/FIB devices such as the helium ion microscope 69 or a dedicated IBL system 39,40,42 but rather with a general purpose focused ion beam device operated at a moderate acceleration voltage of 30 kV and, hence, a machine that is relatively easily accessible. The results point out to the vast potential of the IBL.…”

“…It potentially circumvents the inherent drawbacks of other nanolithography approaches such as the proximity effect in EBL. − While it was considered to be slow, , exotic, and underdeveloped, − the recent progress in advanced focused ion beam (FIB) tools and processes are extremely promising. Incomparable capabilities were developed and are ranging from higher acceleration voltages and optimized beam correction systems with precise interferometrically controlled sample stages , to other systems capable of writing features as small as 10 nm with 30 nm periodicity and processing of large write fields as well as development of He + ion microscopes toward sub-10 nm , down to 4 nm , patterning. In the case of direct milling IBL, the overall smaller number of process steps means that the required expertise field is narrower which makes the process optimization easier and lowers the potential number of fabrication errors.…”

Direct-Write Ion Beam Lithography

“…Because the exposed regions are chemically altered by the implantation, the patterns produced can hold up against some chemical etchants that normally attack the sample material and can serve as mask in wet etching [16,64] or in reactive ion etching [65,66] processes. Examples include gallium ion implantation of silicon wafers (see prior four references), as well as of single crystal diamond [67,68], silicon nitride layers deposited by low-pressure chemical vapor deposition, and germanium selenide layers deposited by thermal evaporation [69,70], aluminum doped zinc oxide, and tantalum layers [2], as well as spin-coated photoresist layers by Arshak et al [61][62][63] as was mentioned earlier.…”

“…High-aspect ratio probe fabrication by the hard masking technique could enable easier batch fabrication and nonstandard probe materials. Silicon [152] and all-diamond [68] probes have been demonstrated by hard masking so far.…”

Morphological and electrical characterization of FIB implanted diamond surfaces

“…FIB induced amorphous carbon has been demonstrated to have optimal masking ability for diamond plasma etching. Tripathi et al [8] used these properties to fabricate high aspect ratio and high resolution patterns. Other studies demonstrate that the non-crystalline layers can be conductive depending on the ion doses used [9,10].…”