Material properties dependence of the peak to valley ratio of heterojunction interband tunneling diodes (HITD) and their use in RF circuits

We report here the development of InGaAs/InAlAs/InP Heterojunction-Interband-Tunneling Diodes (HITD). SIMS and other experimental techniques (TEM, Polaron...) are used to study the effect of dopant compensation and dopant diffusion into the well regions, on the I-V characteristic and the Peak-to-Valley Current Ratios (PVCRs) of the HITDs. The data shows an exponential dependence of the PVCR on Oxygen concentration in the sample. It also shows that the presence of doping impurities in the well region (which is determined using SIMS analysis) has a dramatic effect on the PVCR and the peak current density. Finally, it is mentioned that simulated results confirm the effect of these two mechanisms on the performance of the HITDs and an attempt on studying each separately is made. Use of HITD and Heterostructure Interband Tunneling Field Effect Transistors (HITFETs) enable the design of multifunctional RF circuits having fewer components compared to equivalent FET implementations. To demonstrate the proof of concept, we constructed a hybrid VCO consisting of a GaAs FET and an InP HITD. The VCO exhibited tuning by both Vd and Vg. Further improvements in circuit design and integration should facilitate the fabrication of an InP based integrated VCO.