Conductor-insulator-semiconductor structures for surface-charge transport

摘要

In order to advantageously exploit surface-charge transport of the type recently reported in practical devices, We have utlized a multilevel overlapping molybdenum metallization system. Specific structures will be presented that offer significant improvements in both speed and density over conventional MOSFET's and practical limits will be discussed. These new structures and the processing that produces them are compatible with self-registered MOSFET transistors, so that logic and amplification functions as well as charge-transfer devices are available on the same chip. The mathematical theory of the motion for surface charge is derived and discussed. A key result is that, although the transport equation is a diffusion equation, the effective diffusion constant is several hundred times larger than the thermal diffusivity of the minority carriers. A solution of this equation for shift-register-type device structures and the results of some simple experiments verifying the solution will be presented, and implications for speed and efficiency of charge transfer will be discussed.