LDMOS Deep Well Doping for Breakdown Voltage Stability
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Solution Overview
Problem
Existing semiconductor devices, such as N-type Lateral Double diffused Metal-Oxide-Semiconductor (LDMOS), face limitations in achieving high breakdown voltage due to dopant concentration imbalances and high manufacturing costs associated with fully isolating P-type body regions, which destabilize the breakdown voltage and increase on-resistance.
Innovation Solution
A semiconductor device and method that involve forming a first and second deep well region with different doping concentrations on a substrate, where the first deep well region has a non-planar doping profile and is balanced with a body region, using a mask pattern with stripe patterns to control ion injection and maintain a predetermined dopant concentration, thereby stabilizing the breakdown voltage and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a deep well is extended from drain region to P-type body region to improve breakdown voltage, then breakdown voltage increases to some extent, but breakdown voltage over 100V cannot be obtained
Solution Approach 1:
The patent applies local quality by creating different doping concentration zones within the deep well region. Specifically, it forms a first deep well region with a first doping concentration and a second deep well region with a second doping concentration that is greater than the first. This non-uniform doping profile allows different regions to serve different functions: the lower concentration region maintains high breakdown voltage while the higher concentration region provides stability and reduces on-resistance.
Solution Approach 2:
The patent changes the doping concentration parameter spatially within the deep well structure. By varying the doping concentration from the first deep well region to the second deep well region, the patent optimizes both breakdown voltage and its stability. The parameter change is achieved through selective ion implantation processes with different doses and energies, creating a graded doping profile that resolves the contradiction between achieving high breakdown voltage and maintaining its stability.
2Reliability
If an N-type high concentration N+ buried layer is formed to fully isolate P-type body region from substrate, then breakdown voltage stability improves, but manufacturing cost increases significantly
Solution Approach 1:
Instead of forming a complete N+ buried layer across the entire substrate, the patent applies local quality by forming the second deep well region with higher doping concentration only in specific areas where isolation is needed. This localized approach provides the necessary electrical isolation and breakdown voltage stability while avoiding the high cost and incompatibility issues associated with full substrate isolation.
Solution Approach 2:
The patent replaces the expensive N+ buried layer with a more cost-effective deep well structure that uses moderate doping concentrations. This alternative approach achieves similar electrical isolation and breakdown voltage stability functions without requiring the high-cost fully isolated structure, making the technology compatible with a broader range of applications.
3Loss of energy
If dopant concentration is increased in deep well region to reduce on-resistance, then on-resistance decreases, but breakdown voltage decreases
Solution Approach 1:
The patent resolves this contradiction by applying local quality through spatially varying doping concentrations. The first deep well region with lower doping concentration maintains high breakdown voltage, while the second deep well region with higher doping concentration reduces on-resistance. This localized differentiation allows each region to optimize for its specific function without compromising the other.
Solution Approach 2:
The patent segments the deep well region into multiple zones with different doping characteristics. By dividing the deep well into a first region and a second region with different doping concentrations, the patent enables each segment to contribute differently to the overall device performance, with one segment optimizing for breakdown voltage and another for on-resistance reduction.
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
The approach achieves a higher breakdown voltage while maintaining stability and reducing manufacturing costs by balancing dopant concentrations and using a mask pattern to control ion injection, resulting in improved breakdown voltage and reduced on-resistance.
Implementation Method 1
using a mask pattern with stripe patterns to control ion injection and maintain a predetermined dopant concentration
Data Source
AI summary
Provided is a semiconductor and method of manufacturing the same, and a method of forming even doping concentration of respective semiconductor device when manufacturing multiple semiconductor devices. When a concentration balance is disrupted due to an increase in doping region size, doping concentration is still controllable in example by using ion injected blocking pattern. Thus, the examples relate to a semiconductor and manufacture device with even doping, and high breakdown voltage obtainable as a result of such doping.