Laterally-scaled Si/SiGe n-MODFETs with in situ and ion-implanted p-well doping

The operation of laterally-scaled Silicon (Si)/SiGe n-MODFETs with buried in situ and ion-impanted p-well doping was investigated. The layer stuctures were grown by UHV-chemical vapor deposition (CVD) on 8 inch Si wafers and consisted of a Si 0.7Ge 0.3 bottom barrier layer, a Si quantum well, a top undoped Si 0.7Ge 0.3 spacer layer and a Si cap layer. MODFETs utilizing implanted p-wells were characterized using dc I-V measurements at room temperature. Results show that the devices have improved subthreshold behavior, greatly improved self-gain and improved speed-power product compared with undoped controls.