Poly-Silicon Temperature Sensor Contacts Without Barrier Metal
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Solution Overview
Problem
In semiconductor devices with high-performance structures, the adhesiveness between barrier metals and poly-silicon layers in temperature sensing parts decreases, leading to potential contact failures.
Innovation Solution
The semiconductor device incorporates a poly-silicon diode with a p-type anode and n-type cathode layer in direct contact, without a barrier metal, to enhance adhesiveness and prevent contact failures, particularly in temperature sensing parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a barrier metal is formed between the electrode pad and the poly-silicon layer to suppress contact failure, then the reliability of the contact is improved, but the adhesiveness between the barrier metal and the poly-silicon layer decreases at high temperatures
Solution Approach 1:
The patent removes the barrier metal layer from the contact structure between the poly-silicon layer and the aluminum electrode pad. By extracting this problematic intermediate layer, the patent achieves direct contact between the poly-silicon and aluminum, eliminating the adhesion failure issue that occurred with barrier metals like titanium nitride at high temperatures during device operation.
Solution Approach 2:
The patent creates a composite contact structure consisting of the poly-silicon layer directly contacting the aluminum electrode pad. This composite configuration leverages the complementary properties of both materials - the semiconductor properties of poly-silicon and the high conductivity of aluminum - while avoiding the adhesion problems introduced by intermediate barrier metal layers.
2Reliability
If a barrier metal is introduced to protect the contact, then the contact failure is suppressed, but the contact resistance increases
Solution Approach 1:
The patent removes the barrier metal layer that was causing increased contact resistance. By extracting this intermediate layer, the patent achieves lower contact resistance through direct contact between the poly-silicon and aluminum, while maintaining reliability through the inherent stability of this direct interface.
3Productivity
If a double-sided cooling structure is implemented to dissipate heat, then the discharge rate is improved, but the device complexity increases
Solution Approach 1:
The patent divides the cooling function into two separate sides of the semiconductor substrate, with independent cooling paths on each side. This segmentation allows heat to be dissipated simultaneously from both the front and rear surfaces, effectively doubling the heat dissipation capacity and improving the discharge rate while maintaining manageable structural complexity through modular design.
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 improves the adhesiveness and reduces contact resistance between the poly-silicon layers, effectively preventing contact failures even at high temperatures.
Implementation Method 1
a diode formed by a pn junction between the second-conductivity-type poly-silicon layer and the first-conductivity-type poly-silicon layer
Implementation Method 2
a channel (inversion layer) is formed along a side wall of the trench, in a direction orthogonal to the front surface of the semiconductor substrate
Data Source
AI summary
A source pad of a main semiconductor element is electrically connected to an n+-type source region via a barrier metal. A temperature sensing part is a poly-silicon diode formed by a pn junction between a p-type poly-silicon layer that is a p-type anode region and an n-type poly-silicon layer that is an n-type cathode region. The temperature sensing part is provided, via the field insulating film, on a front surface of a same semiconductor substrate as the main semiconductor element. An anode pad and a cathode pad are in direct contact with the p-type poly-silicon layer and the n-type poly-silicon layer, respectively. The source pad, the anode pad, and the cathode pad are aluminum alloy films.