InGaAs Fin Structure With an Indium-Rich Core for Short-Channel Control
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Solution Overview
Problem
In the manufacturing of integrated circuit devices, indium-rich edges of InGaAs fins are often removed to counter short channel effects, resulting in indium-poor fins with degraded mobility and transistor performance.
Innovation Solution
A technique is developed to maintain an indium-rich core in InGaAs fins by using a buffer layer with an inverse {111} facet profile, promoting indium atom diffusivity away from the sidewalls and towards the fin core, thus minimizing indium loss during fin thinning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the indium-rich edges of InGaAs fins are removed to counter short channel effects, then electrostatic control is improved, but indium content in the fin is depleted resulting in degraded mobility and transistor performance
Solution Approach 1:
The buffer layer with inverse {111} facet profile is prepared in advance before fin formation. This preliminary structural preparation creates a built-in mechanism that directs indium atom diffusion toward the fin core during subsequent processing, ensuring indium enrichment occurs before any trimming operations. The facet profile acts as a pre-configured diffusion guide that compensates for future indium loss during fin thinning operations.
Solution Approach 2:
The invention changes the geometric parameter of the buffer layer interface by creating an inverse {111} facet profile instead of a conventional planar or positive facet structure. This parameter change in the buffer layer geometry fundamentally alters the diffusion behavior of indium atoms, redirecting them from the edges toward the core of the fin structure, thereby maintaining indium content while allowing fin thinning for improved electrostatic control.
2Reliability
If the fin is trimmed thinner to counter short channel effects, then electrostatic control is improved, but indium loss occurs resulting in indium-poor fin
Solution Approach 1:
The buffer layer interface is designed with non-uniform local quality through the inverse {111} facet profile, creating different atomic arrangements and diffusion characteristics at different locations. The facet structure creates regions of high indium diffusivity that channel indium atoms specifically toward the fin core region, while the fin edges experience different diffusion conditions. This local quality variation in the buffer layer interface enables selective indium distribution that compensates for edge removal.
3Ease of manufacture
If conventional deposition is used to form InGaAs fin, then manufacturing is simple, but indium-rich edges and Ga-rich core are formed which requires trimming and results in indium-poor fin
Solution Approach 1:
The buffer layer with inverse {111} facet profile serves as an intermediary structure between the substrate and the InGaAs fin. This intermediary layer mediates the indium distribution by providing a controlled interface that directs indium atom diffusion. Instead of directly depositing InGaAs and dealing with edge enrichment, the buffer layer intermediary creates a built-in mechanism that pre-organizes indium atoms to flow toward the core, simplifying the overall manufacturing by eliminating the need for complex post-deposition indium redistribution processes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures that the indium-rich core is preserved, enhancing electron mobility and transistor performance without significant depletion of indium, thereby improving electrostatic control and reducing short channel effects.
Implementation Method 1
a buffer layer with an inverse {111} facet profile, promoting indium atom diffusivity changes in the channel material in a direction away from the sidewalls
Data Source
AI summary
An apparatus including a transistor device disposed on a surface of a circuit substrate, the device including a body including opposing sidewalls defining a width dimension and a channel material including indium, the channel material including a profile at a base thereof that promotes indium atom diffusivity changes in the channel material in a direction away from the sidewalls. A method including forming a transistor device body on a circuit substrate, the transistor device body including opposing sidewalls and including a buffer material and a channel material on the buffer material, the channel material including indium and the buffer material includes a facet that promotes indium atom diffusivity changes in the channel material in a direction away from the sidewalls; and forming a gate stack on the channel material.