Integrated PN Diode Temperature Sensor in High-Voltage Power Transistors
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Solution Overview
Problem
Micro-pattern trench (MPT) cell designs for high-voltage power transistors lack integrated temperature sensing capabilities, which are essential for accurate temperature monitoring without compromising the existing technology or performance.
Innovation Solution
An integrated pn diode temperature sensor is formed within the semiconductor substrate, using a polycrystalline or amorphous silicon pn diode embedded in dielectric materials, allowing for temperature sensing without altering the base technology or performance of IGBTs or power MOSFETs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If MPT cell design technology is used for high-voltage power transistors, then power losses are reduced and device performance is improved, but temperature sensing capabilities are lost
Solution Approach 1:
The patent combines the temperature sensing function with the existing MPT cell structure by integrating a pn diode sensor within the trench isolation region. This merging allows the device to maintain its low power loss characteristics while adding temperature monitoring capability without requiring separate sensing structures that would compromise the MPT design.
Solution Approach 2:
The trench isolation region in the MPT cell structure is given dual functionality: it continues to provide electrical isolation for the high-voltage power transistor while simultaneously serving as the integration location for the pn diode temperature sensor. This multi-functionality resolves the contradiction by making the isolation structure serve both its original purpose and the new temperature sensing requirement.
2Measurement precision
If temperature sensors are integrated in power transistor dies, then accurate temperature information is provided, but the overall device complexity increases
Solution Approach 1:
The temperature sensor is merged with the existing trench isolation structure rather than being added as a separate component. The pn diode is formed within the same trench region that already provides electrical isolation, eliminating the need for additional isolation structures and reducing overall device complexity while maintaining accurate temperature measurement capability.
Solution Approach 2:
The trench isolation structure serves itself by double-duty: it provides both electrical isolation for the power transistor and houses the temperature sensor. This self-service approach allows the same structural element to fulfill multiple functions, avoiding additional complexity that would arise from completely separate sensor and isolation structures.
3Adaptability or versatility
If pn diode temperature sensor is formed in dielectric material, then temperature monitoring is enabled without altering base technology, but manufacturing process complexity increases
Solution Approach 1:
The pn diode structure is formed during the preliminary stages of the manufacturing process, specifically during the trench isolation formation steps before the power transistor active regions are completely defined. By performing the sensor formation action early in the process sequence, additional manufacturing steps are avoided and the base technology flow is minimally disrupted.
Solution Approach 2:
The formation of the pn diode temperature sensor is merged with the existing trench isolation manufacturing steps. The same dielectric material deposition and patterning processes used for isolation are utilized to create the sensor structure, eliminating the need for separate manufacturing sequences and reducing overall process complexity.
Data Source
AI summary
A method of manufacturing a semiconductor device includes: forming one or more transistor cells in a first region of a semiconductor substrate, the semiconductor substrate having a second region that is devoid of transistor cells; forming a first dielectric material over the first and second regions; forming a second dielectric material over the first dielectric material; forming a pn diode in the first dielectric material over the second region; etching first contact grooves into a p-type region of the pn diode, second contact grooves into an n-type region of the pn diode, and third contact grooves into the first region of the semiconductor substrate at the same time using a common contact formation process; and filling the first contact grooves, the second contact grooves and the third contact grooves with an electrically conductive material.