pocket implant

**Pocket Implant** is an **alternative name for the Halo Implant** — a tilted, localized doping technique that places additional channel-type dopant atoms near the source/drain junction edges to counteract short-channel effects in sub-micron MOSFETs. **Pocket vs. Halo: Same Technique, Different Names** - **Origin**: "Halo" is the more common term in US/European literature. "Pocket" is preferred in some Japanese and Asian references. - **Process**: Identical to halo — tilted implant (15-45°) with wafer rotation, same type as channel doping. - **Purpose**: Increase local doping near S/D junctions to maintain $V_t$ at short gate lengths. **Why It Matters** - **Short-Channel Control**: Essential for sub-100nm planar CMOS to maintain acceptable $V_t$ roll-off characteristics. - **Optimization**: The dose, energy, and tilt angle are carefully tuned to balance $V_t$ control against junction leakage and mobility. - **Obsolescence**: Not needed in FinFET and GAA architectures where undoped channels and compact geometry provide inherent short-channel resistance. **Pocket Implant** is **the halo implant by another name** — the same critical short-channel effect countermeasure, widely used in the planar CMOS era.