Semiconductor Device Gate Electrode Segmentation for Parasitic Bipolar Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor devices face challenges with parasitic bipolar transistors turning on due to overvoltage from Electro-Static Discharge (ESD), leading to potential destruction of MISFETs, as existing designs fail to effectively suppress the turn-on of these transistors, resulting in increased local currents and the need for additional ESD protection elements.
Innovation Solution
The semiconductor device incorporates a gate electrode with first openings or concave portions and a body contact region with higher impurity concentration, which helps in suppressing the potential rise in the body region, thereby preventing the turn-on of parasitic bipolar transistors by providing potential from the body contact region close to the drain regions relative to the source region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional gate electrode design is used, then the device structure is simple, but parasitic bipolar transistors turn on due to ESD overvoltage, leading to increased local currents and potential destruction of MISFETs
Solution Approach 1:
The gate electrode is divided into multiple segments with different configurations (first gate electrode and second gate electrode) that have different widths and positions. This segmentation allows each segment to serve a specific function: the first gate electrode suppresses parasitic bipolar transistor turn-on near the drain, while the second gate electrode maintains normal device operation, thereby improving ESD resistance without requiring a completely new gate structure
Solution Approach 2:
The gate electrode width is varied locally across different regions of the device. The first gate electrode has a narrower width positioned near the drain region where parasitic bipolar transistor formation is most problematic, while the second gate electrode has a wider width in regions where normal operation is prioritized. This local variation in gate width creates different electrical characteristics in different areas, effectively suppressing parasitic transistor turn-on at critical locations
2Reliability
If additional ESD protection elements are added, then ESD resistance improves, but chip area increases and design complexity increases
Solution Approach 1:
The gate electrode structure serves multiple functions simultaneously: it provides normal MOSFET operation, suppresses parasitic bipolar transistor turn-on during ESD events, and eliminates the need for separate ESD protection elements. By making the gate electrode multi-functional, the invention achieves ESD protection without adding dedicated protection components, thereby maintaining compact chip area while improving reliability
3Reliability
If additional ESD protection elements are added, then ESD resistance improves, but design complexity increases
Solution Approach 1:
The gate electrode structure serves multiple functions simultaneously: it provides normal MOSFET operation, suppresses parasitic bipolar transistor turn-on during ESD events, and eliminates the need for separate ESD protection elements. By making the gate electrode multi-functional, the invention achieves ESD protection without adding dedicated protection components, thereby maintaining compact chip area while improving reliability
4Reliability
If the gate electrode width is reduced near the drain, then parasitic bipolar transistor turn-on is suppressed, but the channel width is reduced affecting normal device operation
Solution Approach 1:
The gate electrode is divided into multiple segments with different configurations (first gate electrode and second gate electrode) that have different widths and positions. This segmentation allows each segment to serve a specific function: the first gate electrode suppresses parasitic bipolar transistor turn-on near the drain, while the second gate electrode maintains normal device operation, thereby improving ESD resistance without requiring a completely new gate structure
Solution Approach 2:
The gate electrode width is varied locally across different regions of the device. The first gate electrode has a narrower width positioned near the drain region where parasitic bipolar transistor formation is most problematic, while the second gate electrode has a wider width in regions where normal operation is prioritized. This local variation in gate width creates different electrical characteristics in different areas, effectively suppressing parasitic transistor turn-on at critical locations
Data Source
AI summary
A semiconductor device includes: an n−-type epitaxial layer having an element main surface; a p−-type body region, an n+-type source region, and n+-type drain regions; and a gate electrode including a second opening and first openings formed in a portion separated from the second opening toward the drain regions, wherein the body region selectively has a second portion exposed to the first openings of the gate electrode, and wherein the semiconductor device further includes a p+-type body contact region formed in the portion of the body region exposed to the first openings and having an impurity concentration higher than an impurity concentration of the body region.