Buried Resistors in Buffer Layer for Compound Semiconductor Integration
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Solution Overview
Problem
The semiconductor industry faces challenges in efficiently implementing passive components like resistors in compound semiconductor technologies due to their large layout, which occupies valuable space needed for other components such as FETs, especially when using CMOS technologies.
Innovation Solution
The method involves forming a buried resistor within a buffer layer of a semiconductor device, using a multilayer buffer structure with III-V compound semiconductor materials to minimize mechanical strain and lattice mismatch, allowing for more area in the channel layer for active devices by placing the resistor below the active layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If resistors are fabricated in the active compound semiconductor material layer or gate material layer, then the resistor can be formed using standard CMOS technologies, but the resistor occupies large layout area that detracts from the area available for constructing other components such as FETs
Solution Approach 1:
The patent moves the resistor from the two-dimensional plane of the active layer into the third dimension by forming it in the buffer layer below the active layer. This vertical relocation allows the resistor to occupy space in the z-direction rather than competing for lateral area in the x-y plane, effectively resolving the area conflict while maintaining manufacturability through standard semiconductor processing techniques
2Area of stationary object
If the layout area of resistors is reduced to accommodate more FETs, then more area is available for active devices, but the resistor may not achieve sufficient resistance value or may become difficult to fabricate
Solution Approach 1:
The patent changes the physical parameters of the resistor by forming it in the buffer layer with different material composition and doping characteristics compared to resistors formed in the active layer. This allows the resistor to achieve the required resistance value through vertical positioning and material property adjustments rather than increasing lateral dimensions, thereby maintaining both compact area and manufacturability
Data Source
AI summary
Structures and methods are provided for fabricating a semiconductor device (e.g., III-V compound semiconductor device) having buried resistors formed within a buffer layer of the semiconductor device. For instance, a semiconductor device includes a buffer layer disposed on a substrate, a channel layer disposed on the buffer layer, and a buried resistor disposed within the buffer layer. The buffer and channel layers may be formed of compound semiconductor materials such as III-V compound semiconductor materials. Utilizing the buffer layer of a compound semiconductor structure to form buried resistors provides a space-efficient design with increased integration density since the resistors do not have to occupy a large amount of space on the active surface of a semiconductor integrated circuit chip.