Vertical HEMT Devices Monolithic CMOS Integration
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Solution Overview
Problem
Conventional high electron mobility transistors (HEMTs) cannot be monolithically integrated with CMOS circuitry on the same semiconductor substrate, requiring separate substrates and leading to space inefficiencies and increased stray inductance due to wiring or solder bumps for electrical connection.
Innovation Solution
The formation of vertically oriented heterostructures on the sidewalls of trenches in a silicon substrate allows for the integration of HEMT devices with CMOS circuitry on the same die, eliminating the need for separate substrates and reducing stray inductance by using a silicon substrate with epitaxial silicon and specific crystal orientations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional HEMTs are formed on separate substrates from CMOS circuitry, then electrical connection can be established using wires or solder bumps, but space efficiency decreases and stray inductance increases
Solution Approach 1:
The patent merges HEMT devices and CMOS circuitry onto a single semiconductor substrate by forming HEMTs vertically within trenches in the silicon substrate. This integration eliminates the need for separate substrates and inter-substrate connections, thereby improving space efficiency while maintaining electrical connection reliability through direct on-substrate integration
2Reliability
If conventional HEMTs are formed on separate substrates from CMOS circuitry, then electrical connection can be established using wires or solder bumps, but stray inductance increases
Solution Approach 1:
By combining HEMT devices and CMOS circuitry on the same substrate with vertical HEMT structures formed directly in the silicon, the patent minimizes the length of electrical interconnections. This direct integration significantly reduces stray inductance compared to separate substrate configurations that require long wires or solder bumps for electrical connection
3Area of stationary object
If vertically oriented heterostructures are formed on the same silicon die, then space efficiency improves and stray inductance reduces, but manufacturing complexity increases
Solution Approach 1:
The patent transitions from planar HEMT structures to vertical heterostructures formed within trenches in the silicon substrate. This dimensional change allows multiple HEMT devices to be stacked vertically on the same die area, dramatically improving space efficiency. The vertical configuration is achieved through epitaxial growth of alternating semiconductor layers with different bandgaps within the trench structures
Solution Approach 2:
The patent applies local quality by creating vertically oriented heterostructures with specific crystal orientations (e.g., <110> or <100>) in localized trench regions of the silicon substrate. This allows the HEMT devices to be formed with optimized material properties and crystallographic orientations in specific locations, enabling monolithic integration with CMOS circuitry while managing manufacturing complexity through localized structure formation
Data Source
AI summary
Embodiments are directed to high electron mobility transistor (HEMT) devices and methods. One such HEMT device includes a substrate having a first surface, and first and second heterostructures on the substrate and facing each other. Each of the first and second heterostructures includes a first semiconductor layer on the first surface of the substrate, a second semiconductor layer on the first surface of the substrate, and a two-dimensional electrode gas (2DEG) layer between the first and second semiconductor layers. A doped semiconductor layer is disposed between the first and second heterostructures, and a source contact is disposed on the first heterostructure and the second heterostructure.