RF circuits including transistors having strained material layers
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsGlyn Braithwaite, Richard Hammond, Matthew Currie
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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.
Claims19
A circuit for processing an RF signal comprising at least one FET to which the RF signal is applied, the at least one FET comprising:
- a semiconductor substrate including at least one planarized layer;
- a channel region including at least one strained channel layer disposed on the at least one planarized layer thereby defining an interface therebetween, the at least one strained channel layer having a distal zone away from the interface, wherein the substrate, the interface, and the at least one strained channel layer are characterized at least in part by an impurity gradient having a value substantially equal to zero in the distal zone;
- and
- a gate electrode.
Dependencies are inferred from the claim text.