Semiconductor Doping Profile for ON Resistance and Avalanche Capability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional super junction semiconductor structures face challenges in simultaneously reducing ON resistance and maintaining high withstand voltage, with existing methods either being difficult to implement or increasing production costs and affecting avalanche capability and device reliability.
Innovation Solution
The semiconductor device features a unique doping concentration profile where the difference in net activated doping concentration between n-type and p-type semiconductor regions increases from the first junction plane to the second, optimizing electric field distribution to enhance avalanche capability and reduce ON resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the doping concentration in n-type semiconductor layers is increased to reduce ON resistance, then the ON resistance decreases, but the n-type layers must be depleted to maintain withstand voltage, requiring reduced layer widths and increased aspect ratio
Solution Approach 1:
The patent applies local quality by creating a non-uniform doping concentration distribution within the drift region. Specifically, the doping concentration is designed to increase from the surface toward the bulk, with a gradient profile that provides higher doping near the surface for lower ON resistance while maintaining lower doping deeper in the bulk for adequate depletion and withstand voltage. This localized variation in doping quality resolves the contradiction between reducing ON resistance and maintaining proper depletion characteristics.
2Ease of manufacture
If conventional methods are used to form super junction structure, then the structure can be formed, but implementation is difficult or production costs increase and avalanche capability and device reliability are affected
Solution Approach 1:
The patent employs parameter changes by systematically varying the doping concentration parameter throughout the drift region. The doping concentration is transformed from a uniform value to a graded profile that changes continuously from surface to bulk. This parameter transformation enables easier manufacturing through standard diffusion or ion implantation processes while simultaneously improving avalanche capability by creating optimal electric field distribution that prevents premature breakdown and enhances device reliability.
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 improves avalanche capability, reduces ON resistance, and enhances device reliability by maintaining a higher electric field peak away from the gate electrode, thereby reducing switching noise and increasing the sharpness of output capacity change with drain-source voltage.
Implementation Method 1
when the intensity of the electric field at the pn junction plane reaches a critical electric field, an avalanche breakdown occurs
Implementation Method 2
the depletion layer spreads from a pn junction plane between a p-type base region connected to a source electrode and an n-type drift region
Implementation Method 3
a difference between a charge quantity expressed by an integral value of a net activated doping concentration in the second semiconductor regions and a charge quantity expressed by an integral value of a net activated doping concentration in the first semiconductor region becomes larger from a depth of a first junction plane to a depth of a second junction plane
Data Source
AI summary
A semiconductor device includes a semiconductor substrate of a first conductivity type, a first semiconductor region of the first conductivity type on the semiconductor substrate, and a plurality of second semiconductor regions of a second conductivity type disposed separately in the first semiconductor region. A difference between a charge quantity expressed by an integral value of a net activated doping concentration in the second semiconductor regions in the surface direction of the semiconductor substrate and a charge quantity expressed by an integral value of a net activated doping concentration in the first semiconductor region in the surface direction of the semiconductor substrate is always a positive quantity and becomes larger from the depth of the first junction plane to a depth of a second junction plane on an opposite side from the first junction plane.