Guard Ring Layout for Higher Withstand Voltage in Semiconductors
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Solution Overview
Problem
In semiconductor devices, the spacing between high-voltage-breakdown regions is limited by manufacturing precision, leading to electrical field concentration between these regions when the drift region is depleted, which can result in hot carrier injection into the oxide film, reducing the device's withstand voltage.
Innovation Solution
The semiconductor device incorporates a semiconductor substrate with surface and deep high-voltage-breakdown regions, and a drift region, where the n-type impurity concentration and spacing between these regions are optimized to satisfy specific mathematical relations, dispersing the electrical field and reducing hot carrier generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the spacing between high-voltage-breakdown regions is narrowed to relieve electrical field concentration, then the withstand voltage is improved, but the manufacturing precision requirement increases due to the limited spacing control
Solution Approach 1:
The patent introduces deep high-voltage-breakdown regions at a different depth dimension (below the surface spacing region) to provide an additional pathway for electrical field management. This vertical dimension complementarity allows the device to achieve better electrical field distribution without further constraining the already limited horizontal spacing between surface regions, thereby resolving the contradiction between withstand voltage improvement and manufacturing precision requirements.
2Reliability
If the n-type impurity concentration in the drift region is increased to maintain high withstand voltage, then the electrical field concentration is reduced, but the hot carrier generation increases
Solution Approach 1:
The patent applies local quality by creating deep high-voltage-breakdown regions with specific p-type impurity concentration at particular depth positions. These localized regions provide targeted electrical field management where needed (in the deep spacing region) without requiring uniform changes throughout the entire drift region, thus maintaining high withstand voltage while controlling hot carrier generation in the surface spacing region.
Solution Approach 2:
The deep high-voltage-breakdown regions act as intermediary structures that mediate between the surface spacing region and the bulk drift region. They provide a transition zone that helps distribute the electrical field more evenly, reducing the direct interaction between high electric fields and the oxide film that would otherwise generate hot carriers, while still maintaining the necessary voltage blocking capability.
Data Source
AI summary
A semiconductor device includes a semiconductor substrate, a top electrode in contact with a top surface of the semiconductor substrate, a bottom electrode in contact with a bottom surface of the semiconductor substrate, and an oxide film in contact with the top surface of the semiconductor substrate. The semiconductor substrate includes an element region and an outer peripheral region. The element region is a region where the top electrode is in contact with the top surface of the semiconductor substrate. The outer peripheral region is a region where the oxide film is in contact with the top surface of the semiconductor substrate, and is located between the element region and an outer peripheral end surface of the semiconductor substrate. The element region includes a semiconductor element connected between the top electrode and the bottom electrode. The outer peripheral region includes surface high-voltage-breakdown regions, deep high-voltage-breakdown regions, and a drift region.