Electron resonant tunneling with a high peak-to-valley ratio at room temperature in Si1−xGex/Si triple barrier diodes

We have applied the triple-barrier (TB) structure to a Si1−xGex/Si electron-resonant-tunneling diode (RTD) and have demonstrated that a Si0.7Ge0.3/Si electron tunneling TB RTD exhibits a high peak-to-valley current ratio of more than 7.6 even at room temperature (RT). The results indicate that for a SiGe RTD, a combination of electron tunneling using a tensile-strained Si well structure and well doubling is very effective in enhancing the negative-differential-resistance (NDR) characteristics. Additionally, the large NDR effect at RT is suggestively explained by the simple conduction band configuration and the necessity of the double-well coresonance condition.