Microelectronics manufacturing technology is rapidly moving toward integrated circuits with submicron minimum feature sizes. This is being driven by the development of devices and circuits with reduced device lateral dimensions, increased density per chip, thinner material layers, increased use of the vertical dimension (three-dimensional circuits), low volume/fast tumaround design (ASIC's), increased use of heterojunctions, mixed material technologies, and quantum-based device structures. These trends require precise control of thin layers processed on wafers and a need for lower temperature processing or a lower overall thermal budget

A new analog device, called a Poisson cell, has been developed which aids in obtaining solutions to either Laplace's equation or Poisson's equation. The cell may be used to simulate such potentials as electric potential, magnetic potential, gravitational potential, and the velocity potential of irrotational flow; it has applications in the fields of hydrodynamics, heat conduction, and aerodynamics. The cell is a solid volume-conducting medium made from a homogeneous mixture of hydrostone and graphite. Electrode configurations may be painted on the surface with conducting paint or imbedded directly in the structure. In the case of Poisson's equation, where ∇2ø(x, y) = f(x, y), the function f(x, y) is simulated by injecting currents into the underside of the cell. The application of the Poisson cell to numerous problems and in particular to problems in electron flow is discussed m detail, along with the incorporation of the cell into either an analog computer system or a combined analog-digital computer system.