Optimized blocking impurity placement for SiGe HBTs
AssigneeInternational Business Machines Corporation
InventorsBasanth Jagannathan, Alvin J. Joseph, Xuefeng Liu, Kathryn T. Schonenberg, Ryan W. Wuthrich
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Abstract
A high performance SiGe HBT that has a SiGe layer with a peak Ge concentration of at least approximately 20% and a boron-doped base region formed therein having a thickness. The base region includes diffusion-limiting impurities substantially throughout its thickness, at a peak concentration below that of boron in the base region. Both the base region and the diffusion-limiting impurities are positioned relative to a peak concentration of Ge in the SiGe layer so as to optimize both performance and yield.
Claims20
A high performance SiGe HBT that has a SiGe layer with a peak Ge concentration of at least approximately 20% and a boron-doped base region formed therein having a thickness, wherein said base region includes diffusion-limiting impurities throughout said thickness at a concentration below that of boron in said base region, and wherein said diffusion limiting impurities are physically located relative to both said base region and a portion of said SiGe layer having a Ge concentration of 20% to optimize performance and yield of said SiGe HBT.
A high performance SiGe HBT that has a SiGe layer with a peak Ge concentration of at least approximately 20%, a boron-doped base region formed therein having a thickness, and a region of diffusion-limiting impurities at a concentration, thickness, and spacing relative to said base region and a portion of said SiGe layer having said peak concentration of Ge that optimizes both performance and yield of said SiGe HBT.
A method of producing a SiGe layer on a Si substrate, comprising the steps of:
- introducing germanium atoms during formation of a Si layer, such that at least a portion of said SiGe layer has a peak Ge concentration of at least 20%;
- introducing diffusion-limiting impurities and boron atoms during formation of said Si layer, while said germanium atoms are still being introduced;
- and
- terminating both said diffusion-limiting impurities and said boron atoms approximately simultaneously, said diffusion limiting impurities being introduced at a concentration and for a duration that optimizes both performance and yield.
A SiGe HBT comprising an SiGe layer, a base region, and a diffusion-limiting region, in which said diffusion-limiting region extends substantially throughout said base region and has a dopant concentration less than that of said base region, and wherein both said base region and said diffusion-limiting region are spaced within a given distance of a portion of said SiGe layer having a Ge concentration of at least approximately 20% so as to optimize both performance and yield of said SiGe HBT.
Dependencies are inferred from the claim text.