Simulation of CMOS Fabrication Processes for Double-Insulating Silicon-on-Diamond MOSFET
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2025-04-01 |
| Journal | Journal of Association of Electrical and Electronics Engineers |
| Authors | Hossein Eskandari, Arash Daghighi, Esmaeil Shafaghat |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive SummaryâThis research presents the simulation and implementation of CMOS fabrication processes for a novel 22 nm Double-Insulating Silicon-on-Diamond (DI-SiOD) MOSFET structure.
- Core Innovation: The device utilizes a dual-insulator stack: Diamond (first insulator) for superior thermal management, and Silicon Dioxide (SiO2) (second insulator) for enhanced gate control.
- Thermal Advantage: Diamond acts as an ultra-efficient heat spreader (2000-2400 W/mK), effectively mitigating self-heating effects (SHE) that limit performance in conventional Silicon-on-Insulator (SOI) devices, enabling higher power and frequency operation.
- Electrical Performance: The simulated device demonstrates excellent high-frequency capability, achieving a Unity Gain Cutoff Frequency (fT) of 370 GHz.
- Switching Characteristics: Key metrics include a low Threshold Voltage (Vth) of 0.225 V and a high ON Current (ION) of 45 ”A/”m.
- Fabrication Feasibility: The entire process flow was successfully simulated using standard CMOS fabrication steps, confirming the viability of integrating this advanced structure into existing semiconductor manufacturing lines.
- Value Proposition: DI-SiOD is confirmed to be a superior, advanced replacement for traditional SOI technology, offering improved performance, thermal stability, and better control over short-channel effects (SCEs).
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Technology Node | 22 | nm | Simulated Channel Length |
| Unity Gain Cutoff Frequency (fT) | 370 | GHz | High-Frequency Performance |
| Threshold Voltage (Vth) | 0.225 | V | Operating Point |
| ON Current (ION) | 0.045 | mA/”m | Current at VGS = 1 V, VDS = 0.8 V |
| Diamond Thermal Conductivity | 2000 - 2400 | W/mK | Excellent Heat Dissipation |
| Diamond Bandgap | 5.5 | eV | Ultra-Wide Bandgap (UWBG) |
| Diamond Critical Electric Field | > 8 | MV/cm | High Breakdown Strength |
| Si3N4 Layer Thickness | 0.4 | nm | Ultra-thin layer deposited on Diamond |
| Maximum Constant Current Gain Frequency | 18 | MHz | Frequency where current gain drops |
Key Methodologies
Section titled âKey MethodologiesâThe fabrication process was simulated using standard CMOS techniques adapted for the Double-Insulating Silicon-on-Diamond (DI-SiOD) structure.
- Substrate Preparation: A monocrystalline Silicon wafer is selected and doped to form the P-type body of the transistor.
- First Insulator Deposition (Diamond): A layer of Carbon (Diamond) is deposited onto the Silicon substrate, typically via Chemical Vapor Deposition (CVD), to serve as the primary Buried Oxide (BOX) layer.
- Interface Layer Deposition: An ultra-thin Silicon Nitride (Si3N4) layer (0.4 nm) is deposited over the Diamond. This layer is crucial for preventing amorphous growth and ensuring the subsequent Silicon layer is monocrystalline.
- Second Insulator Deposition (SiO2): Silicon Dioxide (SiO2) is deposited over the Diamond/Si3N4 stack. This layer acts as the secondary insulator to improve gate control and manage short-channel effects.
- Gate Oxide Patterning: Photolithography and etching are used to define the shape and length of the gate oxide (SiO2).
- Gate Stack Formation: Polysilicon (Poly-Si) is deposited over the patterned gate oxide to form the gate electrode.
- Source/Drain Doping: Lightly Doped Drain (LDD) regions are created by implanting Arsenic ions into the Silicon body, followed by thermal annealing to activate the dopants and define the N-type Source and Drain regions.
- Metallization: Aluminum (Al) is deposited and patterned to create the metal contacts for the Source, Drain, and Gate terminals, completing the device structure.
Commercial Applications
Section titled âCommercial ApplicationsâThe superior thermal management and high-frequency performance of the Double-Insulating Silicon-on-Diamond (DI-SiOD) structure make it highly suitable for demanding electronic applications:
- High-Frequency RF and Microwave Systems: The 370 GHz cutoff frequency is critical for next-generation wireless communications (5G/6G), high-speed data links, and advanced radar systems.
- High-Power Density Electronics: Diamondâs thermal conductivity (up to 2400 W/mK) enables the fabrication of robust power MOSFETs and power amplifiers that can handle significantly higher power loads than conventional Si or SOI devices without thermal runaway.
- Extreme Environment Computing: Ideal for applications requiring operation under high ambient temperatures or high-power dissipation, such as aerospace, defense electronics, and industrial control systems.
- Advanced Microprocessors: Provides a platform for high-performance computing (HPC) where minimizing heat generation and maximizing clock speed are paramount.
- Integrated Photonics and Optoelectronics: Leveraging the Diamond layerâs wide bandgap (5.5 eV) and thermal stability for integrated devices that combine electronic and optical functions.