How Flash Memory Stores Data Without Power: Floating-Gate Tunneling Sim

Transistor Micro-Cross-Section & Fowler-Nordheim Energy Band Tunneling

Transistor Controls & Pulses

Control Gate Voltage (Vcg) 0.0 V

Retention Time Scrub 0.0 Years

Ambient Temperature 25 °C

Tunnel Oxide Barrier Thickness 8.5 nm

Physical Telemetry & Semiconductor State

Logic State

BIT 1 (Erased)

Channel Conduction OK

Threshold Voltage (Vth)

1.50 V

Target: 1.5V (1) / 4.8V (0)

Floating Gate Charge (Qfg)

0.00 fC

Trapped electrons count

FN Tunneling Current

0.00 A/cm²

Quantum flux across SiO2

Read Margin Window

1.00 V

Distance from Vread=2.5V

Retention Half-Life

124.5 Yrs

Arrhenius Thermal Model

8-Bit NAND Flash Memory Byte Inspector

Click any memory cell to select and inspect or program its specific floating-gate threshold state.

How Flash Drives Hold Data Without Power: Quantum Tunneling & Charge Trapping

Unlike RAM (which uses capacitors that bleed charge within milliseconds without electricity), USB flash drives rely on Floating-Gate MOSFETs. The floating gate is an electrically isolated poly-silicon conductor completely encased inside a high-quality Silicon Dioxide (SiO₂) insulating barrier.

Fowler-Nordheim Tunneling Current: J_FN = A * E_ox² * exp(-B / E_ox)
Threshold Shift: ΔVth = -Q_fg / C_ox
Arrhenius Charge Leakage: Q(t) = Q_0 * exp(-t * A_0 * exp(-E_a / (k * T)))

When you write data (apply +18V to the Control Gate), a intense electric field (>10 MV/cm) bends the oxide energy barrier. High-energy electrons perform Fowler-Nordheim quantum tunneling straight through the solid insulator into the floating gate.

When power is turned off, the voltage vanishes, and the SiO₂ barrier wall snaps back up to 3.2 eV. The trapped electrons have no energy to cross back. Because SiO₂ resistance exceeds 10²⁰ Ω·cm, the trapped negative charge stays trapped for decades, continually raising the transistor's turn-on voltage (Vth) so that the cell reads persistently as Logic '0'.