MPS Diode Doped Drift Region for Controlled Active-Area Breakdown
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Solution Overview
Problem
MPS diodes experience premature breakdown under reverse bias conditions, leading to degradation and reduced lifetime due to excessive power dissipation in the termination area, which is a small portion of the device.
Innovation Solution
Incorporating a doped region with a higher dopant concentration surrounding the wells, spaced apart from the termination area, to distribute power dissipation across a larger area of the active region, thereby preventing premature breakdown and reducing temperature-induced degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the termination area is used to accommodate high electric field, then breakdown is prevented at the periphery, but power dissipation concentrates in this small area causing temperature increase and degradation
Solution Approach 1:
The invention segments the high electric field accommodation function between two areas: the termination area handles peripheral breakdown prevention, while the doped region in the active area handles power dissipation. This segmentation distributes the thermal load and prevents concentration of power dissipation in the small termination area.
Solution Approach 2:
The doped region acts as an intermediary structure that mediates between the active area and termination area. It provides a controlled breakdown path that dissipates power over a larger area, thereby protecting the termination area from excessive temperature increase while maintaining breakdown prevention functionality.
2Reliability
If breakdown occurs in the termination area, then peripheral breakdown is managed, but excessive power dissipation leads to degradation and reduced device lifetime
Solution Approach 1:
The invention converts the potentially harmful concentration of power dissipation in the termination area into a beneficial distributed breakdown mechanism. By introducing the doped region with controlled breakdown characteristics, the harmful effect of localized power dissipation is transformed into a beneficial distributed power dissipation mechanism that extends device lifetime.
3Ease of manufacture
If the doped region is placed close to the termination area, then manufacturing is simpler, but breakdown may occur prematurely in the termination area
Solution Approach 1:
The invention applies local quality by creating a doped region with specific dopant concentration and spatial distribution in the active area, distinct from the termination area. This local modification allows controlled breakdown in the active area while maintaining the termination area's integrity, achieving both manufacturing feasibility and breakdown control.
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 configuration increases the robustness and lifetime of the MPS diode by minimizing leakage currents and controlling the electrical field, allowing for more controlled breakdown across the active area without affecting the termination area.
Implementation Method 1
the drift region comprises a doped region surrounding each of the plurality of wells and having a higher dopant concentration than a remainder of the drift region, wherein the doped region is spaced apart from the termination area
Implementation Method 2
Wells 104 form respective PN junctions with drift region 103. At lower voltages, MPS diode 100 may operate in a first mode, a depletion region of said PN junctions extends between adjacent wells, thereby preventing or substantially limiting a Schottky current from flowing
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Aspects of the present disclosure generally relate to an MPS diode and a manufacturing method therefor. The MPS diode comprises a semiconductor body including an active area and a termination area adjacent to the active area, wherein the active area comprises a drift region of a first conductivity type, and a plurality of wells of a second conductivity type different from the first conductivity type, the plurality of wells being mutually spaced apart, each well forming a respective PN-junction with the drift region. The MPS diode further comprises a metal layer assembly arranged on a surface of the semiconductor body and comprising at least one metal layer, the metal layer assembly forming a plurality of Schottky contacts together with the drift region and a plurality of respective Ohmic contacts with the plurality of wells. The drift region comprises a doped region surrounding each of the plurality of wells and having a higher dopant concentration than a remainder of the drift region, and wherein the doped region is spaced apart from the termination area.