US 5,705,321 A · Method for manufacture of quantum sized periodic structures in Si materials

Abstract

Multiple-exposure fine-line interferometric lithography, combined with conventional optical lithography, is used in a sequence of steps to define arrays of complex, nm-scale structures in a photoresist layer. Nonlinearities in the develop, mask etch, and Si etch processes are used to modify the characteristics and further reduce the scale of the structures. Local curvature dependent oxidation provides an additional flexibility. Electrical contact to the quantum structures is achieved. Uniform arrays of Si structures, including quantum wires and quantum dots, are produced that have structure dimensions on the scale of electronic wave functions. Applications include enhanced optical interactions with quantum structured Si, including optical emission and lasing and novel electronic devices based on the fundamentally altered electronic properties of these materials. All of the process sequences involve parallel processing steps to make large fields of these quantum structures. The processes are, further, consistent with modern micro lithographic manufacturing practice, promising inexpensive and large-scale manufacture.

Claims14

Dependent claims

In microelectronic processing, the method of fabricating complex two-dimensional quantum-size (less than 30 nanometer) periodic structures in Si materials, the method comprising the steps of:

a. depositing a thin etch mask layer on a Si substrate;
b. depositing a thin photoresist layer on top of the etch mask layer;
c. exposing the photoresist layer with a periodic pattern using a fine-line interferometric lithography technique optimized to yield the appropriate sub-micron dimension of unexposed photoresist;
d. developing the photoresist to remove the exposed photoresist;
e. etching through the etch mask, whereby the developed photoresist pattern is transferred into the etch mask;
f. removing the remaining photoresist;
g. repeating steps b. through f. as required by multiple exposures using the fine-line interferometric lithography technique to obtain the desired pattern;
h. etching the Si substrate with a highly anisotropic etching process, thereby leaving a quantum sized Si structure;
i. repeating steps b. through f. as required to obtain the desired pattern;
j. etching off the remaining etch mask layer, thereby leaving an all Si structure;
k. repeating steps a. through j as required to obtain the desired pattern.

8 more elements

Dependencies are inferred from the claim text.

Method for manufacture of quantum sized periodic structures in Si materials

Life of this patent

Method for manufacture of quantum sized periodic structures in Si materials

Life of this patent

Abstract

Claims14