Semiconductor Guard Ring Layout for Higher Breakdown Strength
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Solution Overview
Problem
Conventional semiconductor devices face challenges in increasing breakdown strength due to the tendency of contact edges to break under reverse bias, limiting their ability to enhance withstand voltage.
Innovation Solution
The semiconductor device incorporates a semiconductor base body with a first semiconductor region, a second semiconductor region acting as a guard ring, and a third semiconductor region functioning as a channel stopper. The total dopant amount in the second semiconductor region (S1) is less than in the third semiconductor region (S2), forming a Zener diode combination that enhances breakdown strength by increasing electric field strength between the regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional guard ring structure is used, then the device structure is simple, but the contact edge is liable to break under reverse bias reducing breakdown strength
Solution Approach 1:
The guard ring structure is segmented into two distinct semiconductor regions: a second semiconductor region (guard ring) and a third semiconductor region (channel stopper). This segmentation allows each region to perform its specific function independently, with the channel stopper preventing harmful field effects at the contact edge while the guard ring provides overall voltage protection, thereby improving both breakdown strength and contact edge reliability
Solution Approach 2:
Different dopant concentrations are applied to different regions: the third semiconductor region (channel stopper) has a higher dopant concentration than the second semiconductor region (guard ring). This local quality differentiation creates a controlled depletion layer extension pattern where the high-dopant channel stopper region prevents depletion layer penetration at the contact edge, locally enhancing reliability without compromising overall breakdown strength
2Strength
If the dopant amount in the guard ring is increased to improve breakdown strength, then breakdown strength increases, but the contact edge becomes more prone to breakdown
Solution Approach 1:
The third semiconductor region (channel stopper) acts as an intermediary element between the second semiconductor region (guard ring) and the first semiconductor region (drift layer). This intermediary region with higher dopant concentration controls the depletion layer extension, preventing it from reaching the contact edge while maintaining the voltage blocking capability of the guard ring, thus eliminating contact edge breakdown without sacrificing breakdown strength
Solution Approach 2:
The dopant concentration parameter is changed locally by introducing a third semiconductor region with higher dopant amount than the second semiconductor region. This parameter change creates a controlled potential well that stops the depletion layer before it reaches the contact edge, preventing contact edge breakdown while maintaining overall breakdown strength through the coordinated structure
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 configuration allows for avalanche breakdown between the second and third semiconductor regions before the contact edge breaks, significantly increasing the breakdown strength of the semiconductor device compared to conventional devices.
Implementation Method 1
allows for avalanche breakdown between the second and third semiconductor regions before the contact edge breaks, significantly increasing the breakdown strength
Data Source
Figure 1(a)~1(b)
Figure 2(a)~2(b)
Figure 3(a)~3(b)
AI summary
A semiconductor device 1 according to the present invention includes a semiconductor base body 10, a first electrode 20, and an insulation layer 30. The semiconductor base body 10 includes: a first semiconductor region 12 of a first conductive type (n-type); a second semiconductor region 16 of a second conductive type (p type) formed at a position where the second semiconductor region 16 is in contact with the first electrode 2o and the insulation layer 30; and a third semiconductor region 18 of a first conductive type (n-type) formed in contact with the second semiconductor region 16 such that the third semiconductor region 18 surrounds the second semiconductor region 16 as viewed in a plan view. In the semiconductor device 1, assuming a total amount of dopants in the second semiconductor region 16 as S1 and a total amount of dopants in the third semiconductor region 18 as S2, a relationship of S1<S2 is satisfied, and a combination of the second semiconductor region 16 and the third semiconductor region 18 has a function of a Zener diode. According to the semiconductor device 1 of the present invention, it is possible to increase breakdown strength compared to a conventional semiconductor device.