# How to Stop Transistors from Wearing Out in Radio Frequency Chips > A method for extending the lifespan of silicon-on-insulator transistors by using a special sink to drain away charge that causes gate oxide breakdown. - **Patent:** US RE48965 - **Original title:** USRE48965E1 - Method and apparatus improving gate oxide reliability by controlling accumulated charge - **Owner:** PSemi Corp - **Granted:** 2022 - **Status:** Active - **Times cited:** 0 - **Field:** semiconductors, telecommunications, consumer_electronics ## What it does This patent describes a technique to prevent the premature failure of transistors used in radio frequency (RF) switches. When transistors are built on a silicon-on-insulator (SOI) substrate, they can accumulate unwanted electrical charge in their body, which stresses the thin gate oxide layer and leads to time-dependent dielectric breakdown (TDDB). The invention adds an 'accumulated charge sink' (ACS) to the transistor body. By applying a negative bias voltage to this sink, the system actively removes the accumulated charge, keeping the gate oxide healthy and extending the life of the device. ## What it does NOT cover - Does not cover standard bulk silicon MOSFETs that do not use an SOI substrate. - Does not cover charge control methods that rely solely on positive bias voltages. - Does not cover transistors lacking a dedicated body contact or sink for charge removal. ## The clever bit The innovation lies in recognizing that the 'body' of an SOI transistor is electrically floating, which allows charge to build up and degrade the oxide. By providing a controlled path to drain this charge using a negative bias, the inventors turned a parasitic effect into a manageable circuit parameter. ## Real-world examples 1. RF front-end modules in 4G and 5G smartphones 2. High-performance antenna switches 3. SOI-based power amplifiers ## Why it matters RF switches are essential components in modern smartphones and wireless hardware, allowing devices to toggle between different frequency bands. As these devices shrink, the gate oxide layers in transistors become thinner and more prone to failure. This technology is critical for ensuring that high-performance RF front-end modules remain reliable over the multi-year lifespan of a consumer device. ## Frequently asked questions ### What does How to Stop Transistors from Wearing Out in Radio Frequency Chips cover? A method for extending the lifespan of silicon-on-insulator transistors by using a special sink to drain away charge that causes gate oxide breakdown. ### Who owns patent US RE48965? PSemi Corp owns this patent, granted in 2022. ### When does this patent expire? This patent is expected to expire on March 8, 2042, when the invention enters the public domain. ### What problem does this patent solve? RF switches are essential components in modern smartphones and wireless hardware, allowing devices to toggle between different frequency bands. As these devices shrink, the gate oxide layers in transistors become thinner and more prone to failure. This technology is critical for ensuring that high-performance RF front-end modules remain reliable over the multi-year lifespan of a consumer device. ### What does this patent NOT cover? Does not cover standard bulk silicon MOSFETs that do not use an SOI substrate. **Full plain-English explainer:** https://patentbrief.org/patent/us/RE48965/google-play-store **Original patent:** https://patents.google.com/patent/USRE48965 --- _Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._ ## Related patents Semantically similar inventions in the PatentBrief corpus: - [How a Special Transistor Reduces Power Leaks in Circuits](https://patentbrief.org/patent/us/12740152/logic-circuit-and-semiconductor-device) — This patent describes a logic circuit that uses a unique transistor made with an oxide semiconductor to drastically cut down on wasted electricity, preventing errors in electronic devices. - [How to Use Air-Gaps to Insulate High-Voltage Semiconductor Chips](https://patentbrief.org/patent/us/RE48450/android-operating-system) — A design for semiconductor chips that uses empty air-filled trenches to provide better electrical insulation for high-voltage transistors without needing complex filling materials. - [How Diodes Make Wireless Amplifiers Clearer](https://patentbrief.org/patent/us/8847689/stacked-amplifier-with-diode-based-biasing) — Qualcomm's patent describes a way to make electronic amplifiers, especially for wireless signals, produce clearer sound by using special diodes to adjust how much power they get based on the signal strength. - [Nanotubes for Better Cooling in Radio Frequency Chips](https://patentbrief.org/patent/us/12740412/rf-devices-with-nanotube-particles-for-enhanced-performance-and-methods-of) — This patent describes a radio frequency device that uses tiny nanotube particles mixed into its protective casing to help the chip stay cooler and work better. - [How Wireless Radios Automatically Adjust to Avoid Signal Overload](https://patentbrief.org/patent/us/12255678/falcon-1) — A method for wireless devices to automatically rearrange their internal signal-processing components when incoming radio signals are too strong and threaten to overwhelm the hardware.