Patent ID: 11899060
Assignee: BATTELLE MEMORIAL INSTITUTE
Field: Measurement (Instruments)
Classification: CPC G  H | IPC G  H

Claim 0:
1. An optical carrier injection method comprising:
applying a pulsed optical beam having pulse duration of 900 femtoseconds or lower on a backside of a substrate of an integrated circuit (IC) wafer or chip, wherein the pulsed optical beam is generated by a laser driven by a radio frequency (RF) signal; and
focusing the pulsed optical beam at a focal point in an active layer disposed on a frontside of the substrate; and
measuring an output signal comprising an electrical signal produced by the IC wafer or chip in response to the carriers injected at the focal point in the active layer using RF lock-in amplification locked to a generated signal at the repetition rate of and phase-locked to the pulsed output of the laser;
wherein a photon energy of the pulsed optical beam is lower than a bandgap of the substrate; and
wherein photons of the optical beam are absorbed at the focal point in the active layer by nonlinear optical interaction to generate carriers at the focal point in the active layer.