Monolithic Compound Semiconductor ESD Protection Structure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional monolithic compound semiconductor structures for electrostatic discharge (ESD) protection require multiple diodes in series, leading to a large die area and limited ESD protection due to the small turn-on voltage of diodes, necessitating a more effective integration of ESD protection components.
Innovation Solution
A monolithic compound semiconductor structure integrating a n-type etching-stop layer and a p-type insertion layer within a BiFET structure, enabling the epitaxial integration of FET, HBT, and thyristor with a pnpn junction, which reduces chip surface area and enhances ESD performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple diodes connected in series are used for ESD protection, then the ESD protection level can be increased, but the die area required increases significantly
Solution Approach 1:
The patent combines multiple ESD protection functions into a single thyristor device with pnpn structure. The thyristor integrates the protection capabilities of multiple diodes while occupying significantly less die area, as the four-layer structure provides high ESD protection level without requiring series connection of multiple separate diode components
Solution Approach 2:
The thyristor structure serves multiple functions simultaneously: it provides ESD protection, voltage clamping, and current limiting in a single device. The pnpn junction structure enables the device to function as both a protection element and a voltage regulator, eliminating the need for separate diodes for each function
2Reliability
If multiple diodes connected in series are used for ESD protection, then the ESD protection level can be increased, but the device complexity increases
Solution Approach 1:
The patent merges multiple ESD protection functions into a single thyristor device with pnpn structure. The thyristor integrates the protection capabilities of multiple diodes while occupying significantly less die area, as the four-layer structure provides high ESD protection level without requiring series connection of multiple separate diode components
Solution Approach 2:
The thyristor structure serves multiple functions simultaneously: it provides ESD protection, voltage clamping, and current limiting in a single device. The pnpn junction structure enables the device to function as both a protection element and a voltage regulator, eliminating the need for separate diodes for each function
3Device complexity
If conventional BiHEMT structure is used, then device integration is improved, but the ESD protection level remains limited due to lack of pnpn junction
Solution Approach 1:
The patent introduces a localized p-type layer within the BiFET structure to create a pnpn junction specifically for ESD protection purposes. This local modification adds thyristor functionality without disrupting the overall BiFET device architecture, maintaining high device integration while enhancing ESD protection capability
Solution Approach 2:
The patent creates a composite structure combining BiFET and thyristor epitaxial structures. The resulting device integrates the high-electron-mobility characteristics of BiFET with the high breakdown voltage and ESD protection capabilities of the pnpn junction thyristor structure
Data Source
AI summary
A monolithic compound semiconductor structure is disclosed. The monolithic compound semiconductor structure comprises a substrate, an n-type FET epitaxial structure, an n-type etching-stop layer, a p-type insertion layer, and an npn HBT epitaxial structure, and it can be used to form an FET, an HBT, or a thyristor.