9310408 Abraham-Shrauner Analytic solutions for the evolution equation of the etched surface of a semiconductor are proposed as a exciting advance. Calculations of the shape of the etching surface for both radical and ion-assisted etching in simple models are feasible in analytic form. The specific model is for etching of a trench on semiconductor such as silicon. Lie group methods for finding the symmetries of nonlinear differential equations will be used to expand the possible class of analytic solutions. These solutions will not only complement numerical simulations of etched surface evolution but in many cases will provide the user with easy expressions that can be quickly applied to the particular etching process. The electric fields due to local charging, chiefly differential charging, will be calculated by finite element analysis with the computer program Maxwell. The deflection of the ion trajectories by the local electric fields will be compared with another mechanism for the distortion, the exclusion of thermal ions with non-normal trajectories by the acceptance solid angle of the trench. *** v s t osed a a $ $ $ ( F / k k / 1 Courier Symbol & Arial 5 Courier New k h h h " h E E E f I R:WW20USERABSTRACT.DOT Cassandra Queen Cassandra Queen

Project Start
Project End
Budget Start
1993-09-01
Budget End
1997-08-31
Support Year
Fiscal Year
1993
Total Cost
$150,478
Indirect Cost
Name
Washington University
Department
Type
DUNS #
City
Saint Louis
State
MO
Country
United States
Zip Code
63130