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US 12,753,068 B2Granted
Engineered substrates, free-standing semiconductor microstructures, and related systems and methods
AssigneeLawrence Semiconductor Research Laboratory, Inc.
InventorsChantal Arena, Nupur Bhargava, Alec Fischer
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Abstract
An engineered substrate comprises a base substrate, a monocrystalline sacrificial intermediate layer epitaxially grown over the base substrate, and a monocrystalline top layer epitaxially grown over the monocrystalline sacrificial intermediate layer. The engineered substrate may be used to form a free-standing microstructure comprising the engineered substrate by removing at least a portion of the intermediate layer from between the base substrate and the top layer.
Claims17
An engineered substrate, comprising:
- a base substrate;
- a monocrystalline sacrificial intermediate layer epitaxially grown over the base substrate;
- wherein a composition of said monocrystalline sacrificial intermediate layer varies across a thickness of the monocrystalline sacrificial intermediate layer;
- wherein the monocrystalline sacrificial intermediate layer comprises a silicon-germanium (Si1-xGex) layer, wherein x denotes a mole fraction of germanium and wherein a value of x is within a range from 0.3 to 0.7;
- wherein the monocrystalline sacrificial intermediate layer comprises a stack of epitaxially grown sublayers and includes a first sublayer and at least a second sublayer formed over the first sublayer, the at least the second sublayer having a lower density of dislocations than the first sublayer;
- and
- a monocrystalline top layer epitaxially grown over the monocrystalline sacrificial intermediate layer.
4 more elements
A free-standing microstructure, comprising:
- a base silicon substrate;
- a monocrystalline sacrificial intermediate germanium-silicon (Si1-xGex) layer epitaxially grown over the base silicon substrate, wherein x denotes a mole fraction of germanium with a value within a range from 0.3 and 0.7, and wherein a value of x varies across a thickness of the monocrystalline sacrificial intermediate Si1-xGex layer;
- wherein the monocrystalline sacrificial intermediate layer comprises a stack of epitaxially grown sublayers and includes a first sublayer and at least a second sublayer formed over the first sublayer, the at least the second sublayer having a lower density of dislocations than the first sublayer;
- and
- a monocrystalline silicon layer epitaxially grown on the monocrystalline sacrificial intermediate Si1-xGex layer;
- wherein one or more voids are present in the monocrystalline sacrificial intermediate Si1-xGex layer directly between the base silicon substrate and the monocrystalline silicon layer.
3 more elements
Dependencies are inferred from the claim text.