FUNCTIONAL DEVICES BASED ON REAL-SPACE TRANSFER IN SI SIGE STRUCTURE/

A charge injection transistor, which operates as an exclusive-OR logic gate, and a monolithic multiterminal device, electrically reprogramma ble between OR and NAND logic function, have been successfully impleme nted in a Si/Si0.7Ge0.3 heterostructure grown by rapid thermal epitaxy on a Si substrate. Room temperature operation of the charge injection transistor is demonstrated, with 10 dB on/off ratio for the exclusive -OR logic function. Microwave measurements indicate a short circuit cu rrent gain cutoff of 6 GHz, for a device with a source-drain distance of 0.5 mu m. Device simulations were used to identify primary dependen cies of the device performance on the parameters used in the design of the structure. Further structural improvements are suggested.