Shared N-Drift Region for LDMOS and Schottky Diode Integration
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Solution Overview
Problem
The integration of high voltage N-LDMOS and Schottky diode devices in integrated circuits requires different doped N-drift regions, leading to increased fabrication costs due to the need for additional photo-masks.
Innovation Solution
A high voltage semiconductor device is designed with a semiconductor substrate featuring a P-body region and an N-drift region, along with a Schottky diode structure, where the N-drift region is shared between the two devices, eliminating the need for separate doped regions and reducing fabrication complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If different concentrated doped N-drift regions are formed for N-LDMOS and Schottky diode devices, then each device achieves its optimal performance, but additional photo-masks are required during fabrication, leading to higher fabrication costs
Solution Approach 1:
The patent merges the N-drift region formation process for both N-LDMOS and Schottky diode devices into a single shared N-drift region. This consolidation eliminates the need for separate doped regions and additional photo-masks, thereby reducing fabrication costs while maintaining the high voltage performance requirements for both device types through optimized doping concentration and depth parameters
Solution Approach 2:
The shared N-drift region serves dual functions: it acts as the high voltage support structure for the N-LDMOS device and simultaneously serves as the drift region for the Schottky diode device. By designing the N-drift region with appropriate doping concentration (1E16 to 1E18 atoms/cm³) and depth (1 to 5 micrometers), it fulfills the high voltage requirements for both device types, achieving multi-functionality
2Manufacturing precision
If separate concentrated doped N-drift regions are formed for N-LDMOS and Schottky diode devices, then each device structure is optimized independently, but the fabrication process complexity increases
Solution Approach 1:
The patent combines the N-drift region formation steps for both device types into a single fabrication process. By using one photo-mask pattern that defines the shared N-drift region covering both the N-LDMOS and Schottky diode active areas, the manufacturing process is simplified while maintaining precise control over doping concentration (1E16 to 1E18 atoms/cm³) and depth (1 to 5 micrometers) to ensure optimal structure for both devices
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 design allows for cost-effective integration of high voltage semiconductor devices with Schottky diodes, maintaining high voltage capabilities while simplifying the fabrication process.
Implementation Method 1
A Schottky junction 122 is created between an anode electrode 160a and the N-drift region 120b
Data Source
AI summary
High voltage semiconductor devices with Schottky diodes are presented. A high voltage semiconductor device includes an LDMOS device and a Schottky diode device. The LDMOS device includes a semiconductor substrate, a P-body region in a first region of the substrate, and an N-drift region in the second region of the substrate with a junction therebetween. A patterned isolation region defines an active region. An anode electrode is disposed on the P-body region. An N+-doped region is disposed in the N-drift region. A cathode electrode is disposed on the N+-doped region. The Schottky diode includes an N-drift region on the semiconductor substrate. The anode electrode is disposed on the N-drift region at the first region of the substrate. The N+-doped region is disposed on the N-drift region at the second region of the substrate. The cathode electrode is disposed on the N+-doped region.