Deep Junction Electronic Device Laser Annealing Process
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Solution Overview
Problem
Current methods for forming deep doped buffer layers on the backside of integrated circuits require high thermal budgets, which is incompatible with the need to maintain the frontside at low temperatures, and are expensive and dependent on high-energy implantation and limited dopant activation.
Innovation Solution
A process involving the deposition of a non-monocrystalline semiconductor layer on a monocrystalline substrate, followed by inactivated dopant incorporation and localized laser thermal annealing to activate dopants and induce epi-like crystallization, allowing for the formation of a deep doped layer at a low thermal budget without high-energy implantation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high energy implantation followed by laser thermal annealing is used to form deep doped buffer layer, then dopant activation is achieved, but the process becomes expensive and strongly dependent on dopant element
Solution Approach 1:
An intermediate non-monocrystalline semiconductor layer is deposited on the monocrystalline substrate to serve as a mediator for dopant incorporation and activation. This intermediate layer enables dopant diffusion and activation without requiring high energy implantation, thereby reducing manufacturing cost and complexity while maintaining reliable dopant activation.
Solution Approach 2:
The mechanical high energy implantation system is replaced with a combination of low energy ion implantation and thermal diffusion through the intermediate layer. This substitution eliminates the need for expensive high energy implanters and reduces strong dependence on specific dopant elements, while still achieving effective dopant activation in the deep buffer layer.
2Reliability
If thermal diffusion is used to activate deeply implanted dopants, then dopant activation is achieved, but the process requires high temperature and long duration resulting in high thermal budget
Solution Approach 1:
The intermediate non-monocrystalline semiconductor layer undergoes phase transition from non-monocrystalline to monocrystalline structure during a controlled thermal processing step. This phase transition enables effective dopant activation and layer crystallization at lower temperatures and shorter durations compared to conventional thermal diffusion, thereby reducing the thermal budget while maintaining reliable dopant activation.
3Length of stationary object
If high energy implantation is used to implant dopant elements directly into buried layer, then deep doped layer formation is achieved, but the process requires expensive high energy implanter and is strongly dependent on dopant element
Solution Approach 1:
An intermediate non-monocrystalline semiconductor layer is deposited preliminarily on the substrate before dopant incorporation. This preliminary action creates a pathway that allows standard low energy implanters to deliver dopants to deep locations through the intermediate layer via diffusion, eliminating the need for expensive high energy implanters and reducing dependence on specific dopant elements.
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 process enables the formation of a deep doped buffer layer with improved doping control and profile, maintaining the frontside at low temperatures and reducing thermal budget, while avoiding the need for high-energy implanters and expensive dopant-dependent activation.
Implementation Method 1
exposing, after the step c), an area of said external surface formed at step b) to a laser thermal anneal beam having a density of energy higher than a determined threshold, so as to melt the layer of non monocrystalline semiconductor material within a volume defined by said laser thermal anneal beam down to an interface with the substrate, and so as to activate said dopant elements incorporated at step c)
Implementation Method 2
so as to melt the layer of non monocrystalline semiconductor material within a volume defined by said laser thermal anneal beam down to an interface with the substrate
Implementation Method 3
Stopping exposure of said area to said laser thermal anneal beam so as to induce epi-like crystallization of said layer of non monocrystalline semiconductor material from said interface with the substrate up to the external surface
Data Source
AI summary
Disclosed is a process for manufacturing a deep junction electronic device including steps of: b) Depositing a layer of non-monocrystalline semiconductor material on a plane surface of a substrate of a monocrystalline semiconductor material; c) Incorporating inactivated dopant elements prior to step b) into said substrate (1) and/or, respectively, during or after step b) into said layer, so as to form an inactivated doped layer; d) Exposing, an external surface of the layer formed at step b) to a laser thermal anneal beam, so as to melt said layer down to the substrate and so as to activate said dopant elements incorporated at step c); e) Stopping exposure to the laser beam so as to induce epi-like crystallization of the melted layer, so that said substrate and/or, respectively, an epi-like monocrystalline semiconductor material, comprises a layer of activated doped monocrystalline semiconductor material.