Si/SiGe Resonant Interband Tunneling Diodes Incorporating $\delta$-Doping Layers Grown by Chemical Vapor Deposition

Abstract

This is the first report of a Si/SiGe resonant interband tunneling diodes (RITDs) on silicon substrates grown by the chemical vapor deposition process. The nominal RITD structure forms two quantum wells created by sharp δ-doping planes which provide for a resonant tunneling condition through the intrinsic spacer. The vapor phase doping technique was used to achieve abrupt degenerate doping profiles at higher substrate temperatures than previous reports using low-temperature molecular beam epitaxy, and postgrowth annealing experiments are suggestive that fewer point defects are incorporated, as a result. The as-grown RITD samples without postgrowth thermal annealing show negative differential resistance with a recorded peak-to-valley current ratio up to 1.85 with a corresponding peak current density of 0.1 kA/cm 2 at room temperature.

Nanometer-Scale Ge-Based Adaptable Transistors Providing Programmable Negative Differential Resistance Enabling Multivalued Logic

“…In comparison with Ge quantum dot tunneling diodes 47 and Si and Si/SiGe resonant interband tunneling diodes, 19,48 the room-temperature PVR of our best performing RFET devices is approximately a factor 10 larger. In total the characteristic of more than 10 similar devices has been measured and analyzed.…”

“…18 Distinct physical methods are currently employed to provide NDR, including resonant tunneling diodes that demand complex semiconductor epitaxial structures, which are difficult to integrate with CMOS. 19 Further, CMOS backend compatible threshold switching in metal/Nb-oxide insulator/ metal structures was shown, but exhibited an inherent deviceto-device variability in the applied threshold current to inhibit current controlled NDR. 20 As a third concept, the Gunn effect discovered by J.…”

“…An example for a simple yet innovative logic element taking advantage of the NDR characteristic is the monostable–bistable transition logic element (MOBILE), employing two NDR devices connected in series capable of performing both NAND and NOR operations. , Furthermore, by stacking more than two NDR devices, an efficient and compact signed-digit NDR-based MVL adder combining a more than 5-fold improvement in circuit propagation delay and a 15 times smaller area compared to common CMOS-based circuits has been proposed . Distinct physical methods are currently employed to provide NDR, including resonant tunneling diodes that demand complex semiconductor epitaxial structures, which are difficult to integrate with CMOS . Further, CMOS backend compatible threshold switching in metal/Nb-oxide insulator/metal structures was shown, but exhibited an inherent device-to-device variability in the applied threshold current to inhibit current controlled NDR .…”

High 5.2 peak-to-valley current ratio in Si/SiGe resonant interband tunnel diodes grown by chemical vapor deposition

“…Recently, the first CVD grown Si/SiGe resonant interband tunnel diodes were reported with a PVCR of 1.85. 13 Optimization of the boron d-doping density was performed to determine conditions to further improve PVCR to 2.95 at room temperature. 14 In this letter, the tunneling barrier thickness is varied from 2 nm to 8 nm, and the highest recorded PVCR of 5.2 is achieved at room temperature for any Si-based tunnel diode epitaxially grown by the CVD technique.…”

The effect of hydrogen on the surface segregation of phosphorus in epitaxially grown relaxed Si0.7Ge0.3 films by rapid thermal chemical vapor deposition

“…As device dimensions are scaled down, a sharp profile of dopants is becoming a key factor to realize nano-scale semiconductor devices such as silicon tunneling diodes, 1 tunneling field effect transistors, 2 and two-dimensional electron gases (2DEGs) in a modulation-doped Si/SiGe heterostructure. 3 2DEGs are of particular interest for quantum dot (QD) applications.…”