Compact MOSFET With Integrated Diode Protection Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor devices with protection circuits using Zener diodes require a large semiconductor substrate, limiting their size reduction due to the need for a significant blank area for Zener diode formation.
Innovation Solution
A semiconductor device with a metal oxide semiconductor field effect transistor (MOSFET) and a protection circuit comprising at least two diodes formed between conductive layers on a semiconductor substrate, where the diodes are defined by a second-conductivity type semiconductor region between first and second first-conductivity type layers, allowing for a more compact design by eliminating the need for a large blank area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Zener diodes are used for protection circuit, then protection against breakdown voltage is achieved, but device size increases due to large substrate requirement
Solution Approach 1:
The protection circuit diodes are merged with the MOSFET structure by forming them in the same semiconductor substrate region. The first and second conductive layers are integrated with the MOSFET gate and drain structures, allowing the protection circuit to share the substrate space with the main device rather than occupying separate area.
Solution Approach 2:
The protection circuit is formed by creating vertical structures using conductive layers stacked above the semiconductor substrate. The first conductive layer (gate) and second conductive layer (drain) are positioned at different vertical levels, with the second-conductivity type semiconductor region forming diodes between them in the vertical dimension, thus reducing horizontal substrate area requirements.
2Reliability
If conventional protection circuit layout is used, then protection function is provided, but manufacturing complexity increases due to separate Zener diode formation
Solution Approach 1:
The protection circuit diodes are merged with the MOSFET structure by forming them in the same semiconductor substrate region. The first and second conductive layers are integrated with the MOSFET gate and drain structures, allowing the protection circuit to share the substrate space with the main device rather than occupying separate area.
Solution Approach 2:
The semiconductor substrate serves multiple functions: it acts as the base for the MOSFET device and simultaneously forms the protection circuit diodes through the same substrate region. The conductive layers serve dual purposes as both MOSFET components and diode terminals, reducing the need for separate dedicated protection circuit structures.
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 enables a more compact semiconductor device construction while maintaining protection against breakdown voltages, as demonstrated by the substitution of the protection circuit in the semiconductor device, allowing for efficient operation without the need for a large substrate.
Implementation Method 1
a protection circuit made of at least two diodes which are defined between the first conductive layer and the second conductive layer
Implementation Method 2
metal oxide semiconductor field effect transistor (MOSFET) formed in the semiconductor substrate
Data Source
AI summary
In a semiconductor device, a metal oxide semiconductor field effect transistor (MOSFET) is formed in a semiconductor substrate, and an isolation layer is formed on the semiconductor substrate so as to extend along a side of the semiconductor substrate. A first conductive layer is formed on the isolation layer along the side of the semiconductor substrate so as to be electrically connected to a gate of the MOSFET. A second conductive layer is formed on the isolation layer along the side of the semiconductor substrate so as to be electrically connected to a drain of the MOSFET. A protection circuit is made of at least two diodes which are defined between the first conductive layer and the second conductive layer.