Patent decision

BL number

O/001/17

Concerning rights in

GB1415353.0

Hearing Officer

Dr L Cullen

Decision date

3 January 2017

Person(s) or Company(s) involved

Element Six Technologies US Corporation

Provisions discussed

Section 14(5)

Keywords

Clarity, Support

Related Decisions

None

Summary

This application concerns high-power solid-state semi-conductor devices and methods of depositing polycrystalline diamond on the surface of non-diamond substrates to provide improved thermal management properties, i.e., more rapid thermal conductivity, reduced cooling requirements, longer component life and greater power handling, in such devices. The applicant found that enhanced thermal management properties can be obtained when the interface layer between the bulk diamond and the non-diamond substrate (for example GaN), more specifically the diamond nucleation layer, has a low thermal boundary resistance. This is achieved by an improved and optimised crystal growth method for diamond on the substrate that results in the diamond nucleation layer being more crystalline than had previously been obtained.

The examiner objected to clarity where the claim to the device was deemed to be defined by a result to be achieved. One of the characterising features used to define the device was the Raman spectrum of the diamond nucleation layer, i.e., the result of a particular test on the product. Raman spectroscopy is a technique known in the art for determining the amount of diamond carbon (sp3) and non-diamond graphitic carbon (sp2) in a sample of diamond. The less sp2 carbon present in the nucleation layer, the more crystalline it is and this increased crystallinity helps reduce thermal boundary resistance and thus improve thermal conductivity. The Hearing Officer (HO) concluded that the Raman spectrum describes the chemical structure of the diamond at this important interface layer and so it can be viewed as representing an essential structural feature of the diamond nucleation layer and therefore does not lack clarity as a result to be achieved.

The examiner also objected to support across the entire ambit of the claims as the application apparently only describes a single embodiment in which the desired result is achieved. Following careful consideration of the application as filed, in particular the relationship between thermal boundary resistance and diamond nucleation density and the impact this has on ability to conduct heat, the HO found that there was sufficient basis for the skilled person, following the claimed method, to arrive at a device with the required Raman and nucleation density characteristics.

The application was remitted back to the examiner for completion of the examination process.

Full decision O/001/17 107Kb