Schottky Diode Latch-Up Prevention in Semiconductor Devices
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Solution Overview
Problem
Conventional semiconductor devices are prone to the latch-up phenomenon, which leads to excessive current generation and potential damage due to the faster voltage level lifting speed of input signals compared to voltage sources, causing parasitic BJTs to conduct and resulting in device failure.
Innovation Solution
Incorporation of a Schottky diode in the semiconductor device, positioned between specific diffusion regions, with a forward bias threshold voltage lower than that of the parasitic BJTs, to prevent conduction of parasitic BJTs when voltage levels are mismatched, thereby avoiding latch-up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional semiconductor structure without Schottky diode is used, then device complexity is low, but latch-up phenomenon occurs causing device failure
Solution Approach 1:
A Schottky diode is introduced as an intermediary component between the input signal and the parasitic BJT structure. The Schottky diode has a lower forward bias threshold voltage than the parasitic BJT, so it conducts first when voltage mismatch occurs, diverting current away from the parasitic BJT and preventing latch-up. This intermediary component resolves the contradiction by adding minimal complexity to achieve significant reliability improvement.
2Reliability
If Schottky diode is added to prevent latch-up, then reliability improves, but device complexity increases
Solution Approach 1:
The invention exploits the parameter difference in forward bias threshold voltages between the Schottky diode and the parasitic BJT. By selecting a Schottky diode with a lower threshold voltage than the parasitic BJT's base-emitter voltage, the system automatically switches current path based on voltage conditions. This parameter-based approach provides reliable latch-up prevention with minimal structural modification.
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
Prevents latch-up phenomena, extending the semiconductor device's lifespan by ensuring it is not easily damaged and maintaining operational integrity even under voltage level mismatches.
Implementation Method 1
The Schottky diode is positioned in the N-well, and utilized for coupled to an input signal. When a voltage level of the input signal is higher than a voltage level of the voltage source, the Schottky diode conducts charges to make the first parasitic BJT and the second parasitic BJT not conducted.
Data Source
AI summary
A semiconductor device of the present invention comprises: a P type semiconductor substrate, an N-well, a first P+ diffusion region, a second P+ diffusion region, a Schottky diode, a first N+ diffusion region, a second N+ diffusion region, a third P+ diffusion region, a fourth P+ diffusion region, a first insulation layer, a second insulation layer, a first parasitic bipolar junction transistor (BJT), and a second parasitic BJT. The Schottky diode is coupled to an input signal. The first N+ diffusion region and the second N+ diffusion region are coupled to a voltage source, respectively. When a voltage level of the input signal is higher than a voltage level of the voltage source, the Schottky diode conducts charges to make the first parasitic BJT and the second parasitic BJT not conducted.