Diamond-AlN Heterojunction Semiconductor for High-Temperature CMOS
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Solution Overview
Problem
Conventional CMOS technology based on silicon is not reliable for stable and continuous operation at high temperatures (above 125° C) due to limitations in thermal stability and mobility.
Innovation Solution
A semiconductor device is developed using a first structural layer of monocrystalline diamond and a second structural layer of monocrystalline AlN or doped AlN, forming a heterojunction structure. The diamond material is subjected to hydrogen-termination treatment in one region to form a two-dimensional hole gas, while a two-dimensional electron gas is formed at the interface with the AlN layer in another region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicon-based CMOS technology is used, then the device can be manufactured with existing processes, but the device cannot operate reliably at high temperatures above 125°C
Solution Approach 1:
The patent changes the fundamental material parameter from silicon to diamond, which has inherently different thermal and electrical properties. Diamond's wide bandgap and high thermal conductivity enable operation at temperatures above 125°C where silicon-based CMOS fails, directly resolving the temperature adaptability contradiction.
Solution Approach 2:
The device employs a composite structure combining diamond substrate with aluminum nitride (AlN) buffer layer and diamond film. This composite material approach leverages the superior thermal properties of diamond while using AlN to manage lattice mismatch and enable epitaxial growth, achieving both high-temperature reliability and manufacturability.
2Reliability
If monocrystalline diamond and AlN heterojunction structure is used, then high-temperature operation and improved performance are achieved, but the manufacturing complexity increases
Solution Approach 1:
The device structure is segmented into distinct functional layers: diamond substrate, AlN buffer layer, and diamond film. Each layer serves a specific purpose - the substrate provides mechanical support and thermal management, the AlN buffer manages lattice mismatch, and the diamond film provides the active semiconductor properties. This segmentation simplifies the manufacturing of complex heterojunctions by treating each layer independently.
Solution Approach 2:
The aluminum nitride (AlN) layer acts as an intermediary between the diamond substrate and the diamond film. It mediates the lattice mismatch between these two materials, enabling epitaxial growth of the diamond film on the diamond substrate while maintaining crystal quality. This intermediary layer reduces the complexity of directly joining dissimilar materials.
3Adaptability or versatility
If hydrogen-termination treatment is applied to diamond, then two-dimensional hole gas is formed for P-type transistor operation, but the process complexity increases
Solution Approach 1:
The hydrogen-termination treatment is applied locally to specific regions of the diamond substrate to create P-type channels where needed. By selectively treating only certain areas, the device achieves versatility in transistor operation (both N-type and P-type) while keeping the surface treatment process relatively simple and targeted, rather than requiring complex global modifications.
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
The semiconductor device achieves stable operation at high temperatures (up to 350° C and above) with improved output power, operating frequency, and breakdown voltage compared to silicon-based CMOS technology.
Implementation Method 1
the second structural layer and the portion of the first structural layer in the first region form a heterojunction structure
Implementation Method 2
a two-dimensional electron gas is formed at an interface between the first structural layer and the second structural layer
Implementation Method 3
the portion of the first structural layer in the second region is subjected to hydrogen-termination treatment
Implementation Method 4
a two-dimensional hole gas is formed at a surface of a portion of the first structural layer
Data Source
AI summary
A semiconductor device has a first region and a second region including a first structural layer, a second structural layer, first electrode structure and second electrode structure. The material of the first structural layer comprises monocrystalline diamond, and a portion of the first structural layer located in the first region is electrically isolated from a portion located in the second region. The second structural layer is disposed on the first structural layer, and located in the first region, and forms a heterojunction structure with the first structural layer; the material of the second structural layer includes a monocrystalline AlN film or a doped monocrystalline AlN film. The first electrode structure comprises a first source electrode, a first gate electrode and a first drain electrode. The second electrode structure comprises a second source electrode, a second gate electrode and a second drain electrode.