Document Type
Thesis
Date of Award
12-31-1990
Degree Name
Master of Science in Electrical Engineering - (M.S.)
Department
Electrical and Computer Engineering
First Advisor
Haim Grebel
Second Advisor
Kenneth Sohn
Third Advisor
Marek Sosnowski
Abstract
Maskless laser-induced etching and plating is a novel technology for etching a three dimensional profile on semiconductor wafers. Using this technique, we may avoid the contaminating mask stage and achieve in-situ monitoring of the on-going process. In this thesis, we have presented findings on light diffraction from an etched pattern in a thin-film cell configuration. We suggest that the etched pattern develops mostly linearly in time with this arrangement, although indirect monitoring of the reaction process such as by light diffraction, should be carefully interpreted. In-situ light diffraction monitoring appear as if light was scattered from an etched pattern developed non-linearly in time. The data may be interpreted, thought, by assuming the existence of a reaction product layer resulting from a linearly developed pattern.
In the second part of this thesis, we describe and attempt to bias the thin-film cell to shorten the etching time. Single-period gratings and two-periods gratings simultaneously etched by two laser frequencies were produced. By using the data of light diffracted from the etched pattern, we can compute the grating profile. This may be found useful when holographic techniques are incorporated in this novel technology.
Since each laser frequency react differently with the semiconductor surface, we have analyzed the temporal dependence of the etching profile resulting from each laser frequency. We revealed that although the profile amplitude develops mostly linearly with time, an amplitude reduction occures after prolonging the etching process. It is much more apparently in the etching process of larger pitch gratings. Reporting on this effect for the first time we believe that an understanding of the mechanism which underlies the laser interaction with the semiconductor surface will enable us to incorporate this technology in the manufacturing line.
The experimental results are reported in the paper: "In-situ Monitoring of Laser-induced Etched Grating on InP: Thin-film cell configuration" by H. Grebel, B. Iskandard, P. Pien, which will be published in Appl. Phys. Lett., (57), Dec, 1990.
Recommended Citation
Pien, Pei-Chen, "Holographic photo-induced electrochemical etching of diffraction grating in n-InP" (1990). Theses. 2904.
https://digitalcommons.njit.edu/theses/2904
