Observation of sharp current peaks in resonant tunneling diode with strained Si0.6Ge0.4/Si(100) grown by low-temperature low-pressure CVD

p-Type double barrier resonant tunneling diodes with high-quality strained Si0.6Ge0.4/Si heterostructures have been realized at low temperatures using the ultraclean low-pressure CVD system. In order to suppress a voltage dro p due to series resistance, the diode structure has been improved with a B- doping concentration in the p(+) contact layers of 10(19)-10(20) cm(-3) The sharp resonant current peaks have been observed from the I-V characteristi cs in the temperature range of 10-200 K. The peak-to-valley current ratio i s as high as 2.9 at 120 K. The peak voltage decreased with increasing tempe rature and hovered around extremely low values with a minimum value of 8 mV at 200 K. The decrease of the peak voltage can be explained mainly by the decrease of the resonant state energy of heavy holes in the quantum well du e to the increase of the hole effective mass, and by the increase of the pe ak energy of the hole distribution in the emitter. A sudden drop of the pea k voltage was found at 110-120 K, and possible processes affecting the obse rved tunneling characteristics are discussed. (C) 2000 Elsevier Science B.V . All rights reserved.