Semiconductor Current Sensor with Segmented Gate Trench
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Solution Overview
Problem
In semiconductor devices, the ratio of current flowing through load transistors and current sensors is affected by process variations and operating conditions, leading to undesirable dependencies.
Innovation Solution
A semiconductor device design featuring a load transistor part and a sensor transistor part with a common gate electrode and field electrode trench structure, where the field electrode trench's maximum dimension parallel to the surface is smaller than its depth, reducing the impact of process variations and operating conditions on current ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common conduction path is used between sensor and load transistor, then device complexity is reduced, but the ratio of sensor current to load current becomes dependent on process variations and operating conditions
Solution Approach 1:
The conduction paths of the sensor transistor and load transistor are electrically separated, creating independent current paths. This segmentation prevents process variations and operating conditions from affecting the current ratio, as each transistor operates independently without shared conduction path dependencies.
2Ease of manufacture
If the field electrode trench has large lateral dimensions, then manufacturing is easier, but the switching characteristics become less homogeneous and switching losses increase
Solution Approach 1:
The field electrode trench is designed with a depth that exceeds its maximum lateral dimension, creating a vertically-dominated geometry. This dimensional change ensures that the field electrode extends deeply into the semiconductor body, providing homogeneous field distribution and improved switching characteristics while maintaining manufacturability through standardized trench formation processes.
Data Source
AI summary
A semiconductor device includes a semiconductor body. The semiconductor body includes a load transistor part and a sensor transistor part. A first source region of the load transistor part and a second source region of the sensor transistor part are electrically separated from each other. A common gate electrode in a common gate trench extends into the semiconductor body from a first surface. A first part of the common gate trench is in the load transistor part, and a second part of the common gate trench is in the sensor transistor part. A field electrode in a field electrode trench extends into the semiconductor body from the first surface. A maximum dimension of the field electrode trench parallel to the first surface is smaller than a depth of the field electrode trench.