Stepped Dielectric Layers for Double Diffused Drain Formation
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Solution Overview
Problem
The existing methods for forming double diffused drains (DDD) in semiconductor devices require thermal annealing and additional masking steps, leading to increased manufacturing costs and complexity.
Innovation Solution
A method involving the use of stepped dielectric layers with different thicknesses to filter high- and low-energy implants, eliminating the need for thermal annealing and masking layers, allowing for simpler and cost-effective formation of DDDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thermal annealing is performed to drive in the first source/drain region, then the desired implantation is achieved, but the process becomes heat intensive and requires extra thermal budget leading to higher manufacturing costs
Solution Approach 1:
The patent applies preliminary action by forming the second source/drain region with a different dopant species before removing the masking layer, rather than performing thermal annealing after both implantations. This reordering of steps eliminates the need for heat-intensive annealing while achieving the desired double diffused drain structure through the selective removal of the masking layer that was deposited after the first implantation
2Manufacturing precision
If a masking layer is used to form the second source/drain region, then the implantation is controlled, but another step is included adding time, money, and preparation to the process
Solution Approach 1:
The patent extracts the masking layer formation step by using the first source/drain region itself as the mask for the second implantation. The first source/drain region, already formed by the first implantation, naturally blocks the dopant during the second implantation, eliminating the need for a separate masking layer and its associated deposition and removal steps
Solution Approach 2:
The first source/drain region serves a dual function: it is both the target of the first implantation and the automatic mask for the second implantation. This self-service approach eliminates the need for external masking layers, reducing process complexity while maintaining precise implantation control
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 simplifies the process by eliminating the need for thermal annealing and masking layers, reducing manufacturing costs and complexity while maintaining the effectiveness of DDDs in semiconductor devices.
Implementation Method 1
implantations are performed through the first and second dielectric layers to form the double diffuse drain regions
Data Source
AI summary
A method of manufacturing double diffused drains in a semiconductor device. An embodiment comprises forming a gate dielectric layer on a substrate, and masking and patterning the gate dielectric layer. Once the gate dielectric layer has been patterned, a second dielectric layer, having a different depth than the gate dielectric layer, is deposited into the pattern. Once the dielectric layers have been placed into a step form, DDDs are formed by implanting ions through the two dielectric layers, whose different filtering properties form the DDDS. In another embodiment the implantations through the two dielectric layers are performed using different energies to form the different dose regions. In yet another embodiment the implantations are performed using different species (light and heavy), instead of different energies, to form the different dose regions.