High-Voltage Semiconductor Layout With Offset Body Contacts
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Solution Overview
Problem
Conventional high voltage semiconductor devices face issues with increased specific on-resistance (Rsp) characteristics and breakdown voltage (BV) due to large separation distances between adjacent gate electrodes and long paths of excess carriers, which also lead to electric field concentration and mask pattern profile deformations.
Innovation Solution
The introduction of a high voltage semiconductor device with a plurality of island-type body contacts spaced apart in a body region, offset from each other along an orthogonal direction, adjacent or overlapping gate electrodes, and the inclusion of a gate field plate to prevent electric field concentration, while maintaining the source area and reducing the separation distance between gate electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional body contact structure is used with sources surrounding the body contact, then the device structure is simple, but the separation distance between gate electrodes increases and specific on-resistance deteriorates
Solution Approach 1:
The body contact is divided into multiple separate body contacts arranged in an array rather than a single surrounded structure. This segmentation allows the gate electrodes to be positioned closer together while maintaining adequate spacing for source regions, thereby reducing the separation distance and improving specific on-resistance characteristics.
Solution Approach 2:
The body contacts are arranged in a two-dimensional array pattern rather than a single central position. This dimensional change allows optimization of both the separation distance between gate electrodes and the path length for excess carriers by distributing body contacts across the device area in multiple rows and columns.
2Ease of manufacture
If the source surrounds the body contact, then the manufacturing process is simple, but the path distance for excess carriers becomes long and breakdown voltage deteriorates
Solution Approach 1:
The single surrounded body contact is segmented into multiple discrete body contacts. Each body contact has its source region extending toward it, creating shorter individual paths for excess carriers. This segmentation reduces the maximum path distance from the drift region to a body contact, improving breakdown voltage while maintaining manufacturability through systematic array placement.
Solution Approach 2:
Different regions of the device have locally optimized source-body contact configurations. Each body contact position is tailored with appropriate source region dimensions and spacing to optimize the local carrier path length, while the overall array maintains consistency for manufacturing. This local optimization ensures short carrier paths throughout the device without requiring a complete redesign of the manufacturing process.
3Device complexity
If body contacts are positioned at the center of the source, then the device structure is symmetric and simple, but the separation distance between gate electrodes increases
Solution Approach 1:
The body contacts are arranged in a two-dimensional array with positions optimized in both horizontal and vertical dimensions. This allows the gate electrodes to be positioned closer together horizontally while body contacts are distributed vertically and horizontally to maintain adequate spacing, effectively reducing the separation distance without compromising device performance.
Solution Approach 2:
Multiple body contacts are distributed across the device area rather than centered in one location. This segmentation allows gate electrodes to be positioned closer together since the body contacts are spread out, with each gate electrode having nearby body contacts that provide adequate spacing and electrical function.
4Area of stationary object
If a single bar-type body contact is used, then the contact area is large, but mask pattern profile deformations occur and source area is reduced
Solution Approach 1:
The single large bar-type body contact is segmented into multiple smaller body contacts arranged in an array. This segmentation reduces the mask pattern complexity for each individual contact, minimizing profile deformations during fabrication. The total contact area is maintained through the distributed array, while each smaller contact is easier to pattern accurately using standard photolithography processes.
Solution Approach 2:
Instead of using one large body contact that requires precise full-coverage patterning, multiple smaller body contacts are used where each contact requires less precise patterning. The cumulative effect of multiple partially distributed contacts achieves the necessary total contact area while reducing the manufacturing precision requirements for each individual contact feature.
Data Source
AI summary
Disclosed are a high voltage semiconductor device and a method of manufacturing the same and, more particularly, a high voltage semiconductor device and a method of manufacturing the same seeking to shorten a path of excess carriers to a body contact and improve breakdown voltage (BV) characteristics accordingly, in addition to minimizing a separation distance between adjacent gate electrodes and improving specific on-resistance (Rsp) characteristics accordingly, by including a plurality of spaced apart body contacts in a body region and offset from each other along a horizontal direction in the semiconductor device.