Semiconductor Temperature Sensing Diode with Trench Electrode
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Solution Overview
Problem
Conventional semiconductor devices with temperature sensing diodes suffer from poor sensitivity and low electrostatic discharge (ESD) resistance due to the layout constraints and thick oxide films, which hinder effective temperature monitoring and surge current handling.
Innovation Solution
A semiconductor device design featuring a temperature sensing diode on the substrate surface with a trench electrode connected to the diode, allowing for improved temperature sensitivity and ESD resistance by optimizing trench dimensions and oxide film thickness, enabling high-speed response and reduced manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the trench width is increased to accommodate thicker polysilicon, then the processing capability improves, but the contact area with the upper electrode decreases and high current cannot be passed
Solution Approach 1:
The invention transitions from a planar contact structure to a three-dimensional structure by forming a trench and filling it with polysilicon. The trench electrode extends vertically into the semiconductor substrate, creating additional contact area in the depth dimension while maintaining a compact surface footprint. This allows thick polysilicon to be accommodated without sacrificing surface contact area.
2Measurement precision
If the trench depth is increased to improve temperature sensitivity, then the temperature monitoring capability improves, but the ESD resistance deteriorates due to thicker oxide film requirements
Solution Approach 1:
The invention applies different oxide film thicknesses to different regions: a thin oxide film (50-500 nm) on the trench inner wall for thermal conduction and temperature sensing, and a thick oxide film (1-10 μm) in the ESD protection region for electrostatic discharge protection. This local differentiation allows simultaneous optimization of temperature sensitivity and ESD resistance.
3Strength
If a thick oxide film is formed on the trench inner wall to improve dielectric strength against ESD, then the ESD protection improves, but the temperature sensitivity inside the semiconductor deteriorates
Solution Approach 1:
The invention applies different oxide film thicknesses to different regions: a thin oxide film (50-500 nm) on the trench inner wall for thermal conduction and temperature sensing, and a thick oxide film (1-10 μm) in the ESD protection region for electrostatic discharge protection. This local differentiation allows simultaneous optimization of temperature sensitivity and ESD resistance.
4Stability of the object's composition
If the temperature sensing diode is located away from the emitter region to avoid heat interference, then the layout stability improves, but the sensitivity to temperature inside the semiconductor deteriorates
Solution Approach 1:
The trench electrode acts as an intermediary that thermally couples the temperature sensing diode (located away from the emitter for stability) to the emitter region (heat source). The thin oxide film in the trench provides a thermal conduction path, allowing the sensing diode to monitor emitter temperature without being directly exposed to heat interference.
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
The solution enhances temperature sensitivity and ESD resistance, allowing for instantaneous temperature monitoring and surge current handling, while reducing manufacturing costs through simultaneous formation of the temperature sensing diode and trench electrode using the same polysilicon film.
Implementation Method 1
a temperature sensing diode made of polysilicon or amorphous silicon is incorporated in an IGBT... By monitoring VF characteristics of this temperature sensing diode, an operating temperature thereof is managed and protected
Implementation Method 2
it is possible to form a trench having a thin oxide film on an inner wall thereof... the thin oxide film... improves sensitivity to temperature inside the semiconductor
Data Source
AI summary
A semiconductor device includes: a semiconductor substrate; a first insulating film on a surface of the semiconductor substrate; a temperature sensing diode on the first insulating film; a trench extending inward from the surface of the semiconductor substrate; and a trench electrode embedded in the trench via a second insulating film and connected to the temperature sensing diode.