Simultaneous BOX and Trap-Rich Layer Formation in SOI Substrates
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The performance of RF devices in silicon-on-insulator (SOI) substrates is affected by parasitic surface conduction due to the capacitor-like configuration, which can be mitigated by incorporating a trap-rich layer between the buried oxide (BOX) layer and the bulk substrate, but existing methods require separate formation of these layers, increasing costs and complexity.
Innovation Solution
A method for simultaneous generation of a buried oxide (BOX) layer and a trap-rich layer in a silicon substrate through oxygen implantation and subsequent annealing, creating a stoichiometric silicon oxide region for the BOX layer and an under-stoichiometric damaged region with defects for the trap-rich layer, thereby reducing parasitic surface conduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate formation methods are used for BOX layer and trap-rich layer, then each layer can be optimized independently, but manufacturing complexity and production cost increase
Solution Approach 1:
The patent combines the formation of the BOX layer and trap-rich layer into a single oxygen implantation process. By controlling oxygen implantation energy and dose, both layers are created simultaneously from one implantation step, eliminating the need for separate formation processes while maintaining independent optimization of each layer's properties
Solution Approach 2:
The oxygen implantation process serves multiple functions simultaneously: it creates the BOX layer at the peak concentration region, forms the trap-rich layer in the trailing edge region, and defines the interface between them. This multi-functional approach reduces manufacturing steps while achieving multiple structural objectives
2Manufacturing precision
If separate formation methods are used for BOX layer and trap-rich layer, then each layer can be optimized independently, but production cost increases
Solution Approach 1:
The patent merges multiple formation steps into a single oxygen implantation process, reducing the number of manufacturing steps required. This consolidation directly reduces production time and cost while maintaining the ability to independently optimize each layer through controlled implantation parameters
Solution Approach 2:
The oxygen implantation process automatically creates both the BOX layer and trap-rich layer with appropriate properties through self-organization of oxygen atoms during implantation and annealing. The process parameters themselves serve to define the distinct regions and their characteristics without requiring additional processing steps
3Ease of manufacture
If traditional SOI substrate structure is used without trap-rich layer, then manufacturing is simpler, but parasitic surface conduction affects RF device performance
Solution Approach 1:
The patent addresses parasitic surface conduction by creating a trap-rich layer that actively traps free charges at the BOX-substrate interface. This layer converts the harmful parasitic conduction effect into a beneficial charge trapping mechanism that prevents signal coupling and improves RF device performance
Solution Approach 2:
The trap-rich layer serves as an intermediary between the BOX layer and the bulk substrate. It acts as a buffer zone that intercepts and traps charges before they can create parasitic conduction paths, thereby protecting the RF devices from the harmful effects of the capacitor-like configuration
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 reduces the cost of SOI substrate production, simplifies the process, and enhances RF device performance by suppressing parasitic surface conduction and improving linearity.
Implementation Method 1
implanting oxygen into the silicon substrate; based on the implanting, producing an implantation concentration profile that includes: a peak at a target depth of the silicon substrate
Implementation Method 2
annealing the silicon substrate thereby simultaneously generating: the BOX layer in a region about the peak, and a first damaged layer in a region below the BOX layer that extends along the trailing edge
Implementation Method 3
presence of the trap-rich layer (130) may produce a trap-rich effect that includes trapping of free charges (e.g., electrons, carriers) underneath the BOX layer (120), thereby preventing flow of current
Data Source
AI summary
Methods for simultaneous generation of a buried oxide (BOX) layer and a trap-rich layer in a silicon substrate are presented. According to one aspect, oxygen is implanted in the silicon substrate such as to form a region of oxygen concentration according to a concentration profile with a peak at a target depth of the BOX layer. According to another aspect, the concentration profile includes a leading-edge profile that is shorter than a trailing-edge profile. According to another aspect, the substrate is annealed to form the BOX layer and a damaged layer immediately below the BOX layer, the damaged layer having a functionality of a trap-rich layer.