SOI field effect transistor element having a recombination region and method of forming same
AssigneeAdvanced Micro Devices, Inc.
InventorsKarsten Wieczorek, Manfred Horstmann, Christian Krueger
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Abstract
An SOI transistor element and a method of fabricating the same is disclosed, wherein a high concentration of stationary point defects is created by including a region within the active transistor area that has a slight lattice mismatch. In one particular embodiment, a silicon germanium layer is provided in the active area having a high concentration of point defects due to relaxing the strain of the silicon germanium layer upon heat treating the transistor element. Due to the point defects, the recombination rate is significantly increased, thereby reducing the number of charged carriers stored in the active area.
Claims26
A field effect transistor formed on a substrate, comprising:
- a substrate having formed thereon an insulating layer;
- a crystalline active region formed on said insulation layer, the crystalline active region including a first region having a first concentration of localized recombination centers and a second region having a second concentration of recombination centers, wherein the second concentration is higher than the first concentration;
- a drain region and a source region;
- and
- a gate electrode electrically insulated from the active region by a gate insulation layer.
A method of forming a transistor element on a substrate, the method comprising:
- providing a substrate having formed thereon an insulating layer;
- forming a first and a second crystalline semiconductor layer, the first and second monocrystalline semiconductor layers having a different lattice constant to create strain in the second semiconductor layer;
- and
- forming a transistor element in and on said first and second crystalline semiconductor layers, wherein one or more heat treatments during the formation of said transistor element reduce said strain and generate a density of point defects in said second semiconductor layer that is higher than a density of point defects in the first semiconductor layer.
Dependencies are inferred from the claim text.