Abstract:
Semiconductor structures and devices including strained material layers having impurity-free zones, and methods for fabricating same. Certain regions of the strained material layers are kept free of impurities that can interdiffuse from adjacent portions of the semiconductor. When impurities are present in certain regions of the strained material layer, there is degradation in device performance. By employing semiconductor structures and devices (e.g., field effect transistors or "FETs") that have the features described, or are fabricated in accordance with the steps described, device operation is enhanced.
Abstract:
Circuits for processing radio frequency ("RF") and microwave signals are fabricated using field effect transistors ("FETs") that have one or more strained channel layers disposed on one or more planarized substrate layers. FETs having such a configuration exhibit improved values for, for example, transconductance and noise figure. RF circuits such as, for example, voltage controlled oscillators ("VCOs"), low noise amplifiers ("LNAs"), and phase locked loops ("PLLs") built using these FETs also exhibit enhanced performance.
Abstract:
A method is disclosed for isolating device regions in a heterostructure that includes at least one layer of a strained semiconductor material. The method includes the steps of forming a trench in the at least one layer of strained semiconductor material using an etch chemistry that is selected to etch different layers of said heterostructure sufficiently similarly that said trench includes walls that are substantially straight, and depositing a dielectric material in the trench.
Abstract:
A semiconductor structure including a relaxed Si1-xGex layer on a substrate, a strained channel layer on said relaxed Si1-xGex layer, and a sacrificial Si1-yGey layer. The sacrificial Si1-yGey layer is removed before providing a dielectric layer. The dielectric layer includes a gate dielectric of a MOSFET. In alternative embodiements, the structure includes a Si1-zGey spacer layer and a Si layer. In another embodiment of the invention there is provided a method of fabricating a semiconductor device including providing a semiconductor heterostructure, the heterostructure having a relaxed Si1-xGex layer on a substrate, a strained channel layer on the relaxed Si1-xGex layer, and a Si1-yGey layer; removing the Si1-yGey layer; and providing a dielectric layer.