Nonoverlapping dual-gate bucket-brigade devices

Abstract

A novel bucket‐brigade charge‐transfer device concept is presented and experimentally verified. The dual‐gate BBD exhibits operational performances comparable to surface‐channel charge‐coupled devices, while still enjoying fabrication simplicity and high yield. The concept is implemented using conventional p‐channel aluminum‐gate technology with only an additional shadowed‐gap lift‐off process which produces self‐aligned bias‐gate electrodes separated from the adjacent clock buses by submicron (typically 0.5 μm) spacings. Transfer inefficiencies below 10⁻⁴ at 100 kHz and around 5×10⁻⁴ at 1 MHz have been currently observed, despite the low carrier mobility (140 cm²/V s).