Source-Drain Superlattice Contacts for Lower Semiconductor Resistance
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Solution Overview
Problem
Existing semiconductor devices face challenges in achieving enhanced charge carrier mobility and reduced contact resistance, which affect performance and efficiency.
Innovation Solution
The use of dopant diffusion blocking superlattices, such as Si/O superlattices, to divide source and drain regions, combined with oxygen insertion layers near the metal-semiconductor interface, to trap dopants and reduce Schottky barrier height and contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If dopant concentration in source and drain regions is increased to reduce contact resistance, then contact resistance decreases, but dopant diffusion into the channel region increases causing performance degradation
Solution Approach 1:
The source and drain regions are segmented into multiple zones with different dopant concentrations by inserting superlattice barrier layers. The superlattice divides the doped region such that high dopant concentration can be maintained near the contact without allowing diffusion into the channel, creating distinct dopant concentration zones that resolve the contradiction between low contact resistance and low dopant diffusion.
Solution Approach 2:
The superlattice barrier layer acts as an intermediary between the heavily doped source/drain contact region and the channel region. This intermediate structure prevents direct dopant diffusion while allowing the high dopant concentration needed for low contact resistance to exist in the upper region, thus mediating between the conflicting requirements.
2Speed
If strained material layers are used to enhance charge carrier mobility, then device speed and performance improve, but manufacturing complexity increases
Solution Approach 1:
The patent modifies the crystal structure parameters of the semiconductor material by introducing strained material layers with different lattice constants. This changes the band structure and effective mass of charge carriers, thereby enhancing mobility without requiring fundamental changes to the manufacturing process, thus improving speed while managing manufacturing complexity.
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 enhances charge carrier mobility and reduces contact resistance, leading to improved device performance and efficiency by lowering the effective mass of charge carriers and stabilizing the interface with metal contacts.
Implementation Method 1
at least one oxygen monolayer constrained within a crystal lattice of adjacent base semiconductor portions
Implementation Method 2
applying heat to move upward oxygen atoms from the at least one oxygen monolayer to react with the at least one metal layer
Data Source
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AI summary
A method for making a semiconductor device may include forming spaced apart source and drain regions (1021, 103') in a semiconductor layer (101') with a channel region (130') extending therebetween. At least one of the source and drain regions may be divided into a lower region (104', 106') and an upper region (105', 107') by a dopant diffusion blocking superlattice (125') with the upper region having a same conductivity and higher dopant concentration than the lower region. The method may further include forming a gate (108') on the channel region, depositing at least one metal layer on the upper region, and applying heat to move upward non-semiconductor atoms from the non-semiconductor monolayers to react with the at least one metal layer to form a contact insulating interface between the upper region and adjacent portions of the at least one metal layer.