SINGLE-HETEROJUNCTION STRUCTURES FOR ACOUSTIC CHARGE-TRANSFER DEVICES

Numerical studies are reported of possible epitaxial layer structures for an acoustic charge transfer device in which charge confinement is provided by a single heterojunction. These devices were modelled to fi nd structures providing adequate charge confinement and minimal backgr ound charge. It is found that, to avoid parasitic signals at the frequ ency of the surface acoustic wave, it is necessary to have minimal cha rge in the accumulation layer at the heterojunction interface. The lev el of parasitic signal obtained using a single heterojunction acoustic charge transfer det ice is compared with that obtained using a quantu m well acoustic charge transfer device.