Micro Asperity Contact Mechanics in Millimeter Wave Test Socket Interfaces
Mechanical preload across socket micro asperities defines insertion loss stability and constriction resistance in millimeter wave automated device testing.
Sharvin Resistance
Meaning
Theoretical limit of electrical resistance that occurs when the dimensions of a conductor are smaller than the electron mean free path. Sharvin resistance arises in extremely small contacts where electrons pass through without scattering. This behavior marks the transition from classical physics to quantum transport.
Ballistic Flow
Electrons move through a sharvin contact as ballistic projectiles. Because there is no scattering within the contact itself, the resistance depends only on the number of available paths for the electrons. This results in a minimum resistance that cannot be lowered by improving the material purity.
The phenomenon occurs when the physical diameter of the junction is smaller than the distance an electron travels between collisions.
Microscopic Scale
Conductance is proportional to the cross sectional area of the contact. As devices shrink toward the nanometer scale, this effect becomes a dominant factor in the performance of interconnects. It represents the final limit of how small a wire or contact can be while still carrying a useful current.
Theoretical Limit
Low temperature experiments are often used to observe this phenomenon clearly. At room temperature, other forms of scattering usually hide the sharvin resistance. Understanding this limit is necessary for the design of molecular electronics and advanced semiconductor gates.
The value represents the highest possible conductance for a contact of a given size.