US 12,106,968 B2 · Injection metal assisted catalytic etching

Abstract

An electroless etching process. The process produces nanostructured semiconductors in which an oxidant (Ox1) is deposited as a metal on a semiconductor surface and used as a catalytic agent to facilitate reaction between a semiconductor and a second oxidant (Ox2). Ox2 is used to initiate etching by injecting holes into the semiconductor valence band as facilitated by the catalytic action of the deposited metal. The extent of reaction is controlled by the amount of Ox2 added; the reaction rate is controlled by the injection rate of Ox2. The process produces high specific surface area and/or hierarchically structured porous Si with higher and controllable yield. In addition, the ability is demonstrated to vary the pore size distribution of mesoporous silicon including producing hierarchically structured mesoporous silicon with more than one peak in the pore size distribution. In principle, the process applies to any semiconductor onto which metal can be deposited galvanically.

Claims15

Dependent claims

A process to improve control of electroless etching to produce porosified or hierarchical silicon particles comprising the steps of:

(a) providing electronics-grade, metallurgical-grade, or other silicon-comprising powders;
(b) adding a first oxidant, which deposits on the powder as a metal catalyst for electroless etching;
by injecting via a pump a first solution containing a soluble form of the metal catalyst by controlling an injection rate to facilitate metal loading with an even deposition of the metal catalyst, having a controlled coverage between 0.024 mmol and 0.6 mmol per square meter with respect to a surface area of the silicon-comprising powder before etching;
(c) initiating electroless etching to engender nanostructure formation through injection with a controlled rate and amount of a second solution containing a second oxidant;
and
(d) wherein the nanostructure formation defines a pore size distribution with a mean pore size of between 4.3 nm and 24.2 nm and a BJH pore volume of 0.12-1.1 cm3/g.

3 more elements

Dependencies are inferred from the claim text.

Injection metal assisted catalytic etching

Life of this patent

Injection metal assisted catalytic etching

Life of this patent

Abstract

Claims15