Trench Contact Diode Doping Profile for Lower Vf Switching
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Solution Overview
Problem
Existing semiconductor devices face challenges in optimizing the doping concentration profiles, particularly in the anode region, which affect the switching performance and ON voltage of transistors, as the current designs often result in increased Vf with deeper trench contact portions.
Innovation Solution
The semiconductor device employs a modified doping concentration profile with a peak position deeper than the bottom portion of the trench contact portion and a positive slope, along with a manufacturing method involving multiple ion implantation steps with varying acceleration voltages to form a flat region with sufficient doping concentration, thereby controlling the Vf change rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the trench contact portion is made deeper to improve transistor performance, then the switching performance is improved, but the ON voltage (Vf) increases
Solution Approach 1:
The patent applies parameter changes by modifying the doping concentration profile through multiple ion implantation steps with different acceleration voltages. A first ion implantation at a higher acceleration voltage creates a deeper doping profile, while a second ion implantation at a lower acceleration voltage adjusts the surface concentration. This dual-implantation approach optimizes the doping distribution to reduce ON voltage while preserving the deep trench contact structure needed for good switching performance.
2Loss of energy
If the doping concentration is increased to reduce ON voltage, then the ON voltage decreases, but the switching performance deteriorates
Solution Approach 1:
The patent applies local quality by creating different doping concentration regions at different depths. The first ion implantation at higher acceleration voltage provides deep doping for switching performance, while the second ion implantation at lower acceleration voltage provides surface doping for reduced ON voltage. This spatial differentiation of doping quality allows simultaneous optimization of both switching performance and ON voltage characteristics.
3Ease of manufacture
If a single ion implantation step is used to simplify manufacturing, then the manufacturing process is simplified, but the doping concentration profile cannot be optimized
Solution Approach 1:
The patent applies segmentation by dividing the doping process into two distinct ion implantation steps. The first step uses a higher acceleration voltage to create deep doping for switching performance, while the second step uses a lower acceleration voltage to adjust surface concentration for ON voltage optimization. This segmented approach enables precise control of the doping concentration profile that cannot be achieved with a single implantation step.
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
This approach effectively suppresses the increase in Vf and maintains a stable doping concentration around the trench contact portion, improving the switching performance and reducing ON voltage by optimizing the doping concentration profile.
Implementation Method 1
a manufacturing method involving multiple ion implantation steps with varying acceleration voltages
Data Source
AI summary
There is provided a semiconductor device that includes a diode portion, the semiconductor device including: a drift region of a first conductivity type provided in a semiconductor substrate; an anode region of a second conductivity type provided to be closer to a front surface side of the semiconductor substrate than the drift region; and a trench contact portion provided at a front surface of the semiconductor substrate in the diode portion, in which in a depth direction of the semiconductor substrate, a doping concentration of the anode region at a same depth as that of a bottom portion of the trench contact portion is 1E16 cm−3 or more and 1E17 cm−3 or less.