Steep Doping Profile via Selective Laser Annealing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for producing steep dopant profiles in semiconductor components, such as laser annealing in the melt mode, face challenges like thermomechanical strains and delamination due to oxide layer melting, necessitating masking and limiting miniaturization and integration density.
Innovation Solution
A method involving laser irradiation of a semiconductor body with a preprocessed substrate, using a layer stack as a mask to protect adjacent regions and maintain structural composition, allowing for steep doping profiles without outdiffusion and delamination, by selectively melting and recrystallizing the dopant-implanted region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser annealing in the melt mode is used to activate dopants, then dopant activation degree and steep doping profile are improved, but thermomechanical strains and delamination occur due to oxide layer melting
Solution Approach 1:
The invention segments the treatment process by spatially separating the regions subjected to melt-mode laser annealing. Only the semiconductor regions requiring dopant activation are melted, while oxide-covered regions are protected and remain unmelted. This is achieved through selective masking or direct selective laser irradiation, allowing the process to proceed without the harmful effects of oxide layer melting while still achieving the desired steep doping profiles in the active regions.
Solution Approach 2:
The invention applies local quality by differentiating the treatment applied to different regions of the semiconductor substrate. Active regions receive full melt-mode laser annealing for maximum dopant activation, while oxide-covered or non-active regions receive reduced or no laser energy to prevent melting. This localized approach allows each region to receive the appropriate treatment for its specific function, achieving steep doping profiles where needed while maintaining structural integrity where oxide layers are present.
2Reliability
If masking is used during laser annealing to protect oxide regions, then delamination is prevented, but process complexity and manufacturing steps increase
Solution Approach 1:
The invention employs preliminary action by preparing the semiconductor substrate in advance with oxide layers or protective structures in specific regions before the laser annealing process. These pre-formed oxide layers or protective masks are deposited or grown beforehand, and then the selective laser annealing is performed. This preliminary preparation allows the subsequent laser process to proceed without requiring complex real-time masking, as the protective elements are already in place to prevent delamination during annealing.
Solution Approach 2:
The invention utilizes self-service by designing the process so that the oxide layers or protective structures serve dual purposes: they protect the semiconductor regions during subsequent processing steps and simultaneously act as the masking layer during laser annealing. The oxide layers that are grown or deposited for their primary function of protecting the semiconductor surface also serve as the protective mask during laser annealing, eliminating the need for separate masking materials and reducing process complexity.
3Productivity
If component dimensions are shrunk to increase integration density, then cost savings are achieved, but dopant profiles must be produced ever more steeply
Solution Approach 1:
The invention applies parameter changes by utilizing melt-mode laser annealing with specific energy densities and pulse durations to achieve extremely steep dopant profiles. By controlling the laser parameters (energy density, pulse width, wavelength) and the melting conditions, the process achieves dopant activation and profile formation with vertical gradients that are much steeper than conventional thermal annealing can produce. This enables the continued miniaturization of components while maintaining the required dopant profile precision for high integration density.
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 enables the formation of semiconductor zones with steep doping profiles, achieving high dopant concentrations while minimizing lateral outdiffusion and maintaining the structural integrity of the semiconductor body, thus supporting miniaturization and integration density goals.
Implementation Method 1
The semiconductor body is irradiated with laser radiation in order to activate the dopants by melting at least the partial region of the semiconductor body
Implementation Method 2
at least the partial region is melted
Implementation Method 3
at least the partial region recrystallizes
Implementation Method 4
previously implanted dopants are dissolved in the melt and incorporated at lattice sites during the recrystallization
Data Source
AI summary
An integrated circuit and method, producing semiconductor zones with a steep doping profile is disclosed. In one embodiment, dopants are implanted in a region corresponding to the semiconductor zone to be formed and which has at least one topology process. During the subsequent laser irradiation for activating the dopants in the semiconductor zone, regions which are laterally directly adjacent to the semiconductor zone are protected against melting on account of the topology process.