Ultra-large-size silicon device with diamond-based heat dissipation and preparation method thereof

A ultra-large-size silicon device with diamond-based heat dissipation, wherein the ultra-large-size silicon device is prepared by a method comprises the following steps:

• S1:
• cleaning and drying a monocrystalline silicon wafer at room temperature;
• S2:
• subjecting the monocrystalline silicon wafer to a seeding pretreatment process to deposit a diamond nanocrystalline layer across a silicon surface, then transferring the seeded monocrystalline silicon wafer into a microwave plasma chemical vapor deposition (MPCVD) equipment, wherein the MPCVD equipment has a microwave source of 915 MHz or 433 MHz;
• S3:
• evacuating a chamber of the MPCVD equipment, performing hydrogen purging, then performing re-evacuation;
• subsequently, introducing hydrogen gas and regulating a chamber pressure to 5-8 torr to initiate plasma ignition;
• S4:
• increasing microwave power to 70-75 kW with a rate of 4.5-5.5 kW/min, elevating the chamber pressure to 165-180 torr with a rate of 10-30 torr/min, and increasing chamber temperature to 900-950° C. with a rate of 55-65° C./min;
• S5:
• introducing growth gases with the following flow rates:
• hydrogen (H2) at 5000-6000 sccm, methane (CH4) at 100-150 sccm, oxygen (O2) at 5-8 sccm, nitrogen (N2) at 1-2 sccm, and argon (Ar) at 800-1000 sccm;
• S6:
• upon completion of diamond growth, initiating a cooling process with a temperature decrease rate of 25-35° C./min until room temperature is reached, followed by venting the chamber with nitrogen gas, thereby obtaining a ultra-large-size polycrystalline diamond film;
• S7:
• grinding and polishing the silicon surface of the ultra-large-size polycrystalline diamond film to achieve partial silicon removal while retaining a silicon substrate with a thickness of 50 nm to 50 μm;
• S8:
• depositing a coating on the silicon surface of the ultra-large-size polycrystalline diamond film, wherein a coating material is selected from a group consisting of titanium (Ti), chromium (Cr), nickel (Ni), or their combinations;
• S9:
• upon completion of coating deposition, performing copper plating on the silicon surface of the ultra-large-size polycrystalline diamond film with a plating thickness of 10 nm-2000 nm;
• S10:
• obtaining two copper-plated ultra-large-size polycrystalline diamond films, followed by performing cleaning and surface treatment on their copper surfaces;
• and
• S11:
• subjecting the two copper-plated ultra-large-size polycrystalline diamond films to Cu-Cu bonding on their copper surfaces, wherein the bonding process comprises:
• conducting room-temperature alignment and pre-bonding in ambient atmosphere, followed by final bonding under a vacuum condition at a temperature of 180-220° C. and a pressure of 1.8-2.2 MPa for 25-35 minutes.