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2D Materials Forum (17 April 2015)

Wong Pei Yu Calvin
Fri, 17/04/2015 - 12:15pm to 1:15pm
S16, Level 6, Theory conference room
Liu Song
Event Type: 

Title: Graphene as protection barriers to prevent unwanted doping in electronic devices

Speaker: Wong Pei Yu Calvin (PhD Student)

 Time and location: April 17th, Friday, 12:15, S16, Level 6, Theory conference room

 Abstract: Diffusion barriers prevent materials from intermixing (e.g., undesired doping) in electronic devices. Most diffusion barrier materials are often very specific for a certain combination of materials and/or change the energetics of the interface because they are insulating or add to the contact resistances. In my talk, I present graphene (Gr) as an electronically transparent diffusion barrier in metal/semiconductor devices, where Gr prevents Au and Cu from diffusion into Si, and unintentionally dope Si. We studied the electronic properties of the n-Si(111)/Gr/M Schottky barriers (M = Au or Cu) by I(V) measurements and at the nanoscale by ballistic electron emission microscopy (BEEM). The layer of Gr does not change the Schottky barrier of these junctions.

The Gr barrier was thermally and mechanically stable enough to withstand the harsh fabrication methods typically encountered in clean room processes (e.g., deposition of metals in high vacuum conditions at high temperatures), it is electronically transparent (it does not change the energetics of the Si/Au or Si/Cu Schottky barriers), and effectively prevented diffusion of the Cu or Au into the Si at elevated temperatures. Applications of the Gr diffusion barrier in c-Si based photovoltaics and molecular electronics will be discussed.


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