We demonstrate the characteristics of p+-Ge/n-Si and n +-Ge/p-Si heterojunction diodes with a very high on/off ratio and very low leakage current using heteroepitaxial Ge grown directly on Si. The current ratio of p+-Ge/n-Si and n+-Ge/p-Si heterojunction is ∼5 × 107 and ∼3 × 106, respectively. The remarkably low off current density is 2.1 μA/cm2 for p+-Ge/n-Si and 19 μA/cm2 for n+-Ge/p-Si at a reverse bias of |VF| = ±1 V, respectively. High on current density (125 A/cm2 for p+-Ge/n-Si and 54 A/cm 2 for n+-Ge/p-Si) with a forward bias |VF| = ±1 V is obtained with a GeO2 passivation and an Al 2O3 isolation.
|Journal||Applied Physics Express|
|State||Published - 1 Feb 2013|