Abstract
In this work, we experimentally investigate the impact of electrical stress on the tunability of single hole transport properties within a p-type silicon MOSFET at a temperature of T = 2 K. This is achieved by monitoring Coulomb-blockade from three disorder based quantum dots at the channel-oxide interface, which are known to lack tunability as a result of their stochastic origin. Our findings indicate that when applying gate biases between −4 V and −4.6 V, nearby charge trapping enhances Coulomb-blockade leading to a stronger quantum dot confinement that can be reversed to the initial device condition after performing a thermal cycle reset. Re-applying stress then gives rise to a predictable response from reproducible changes in the quantum dot charging characteristics with consistent charging energy increases of up to ≈50% being observed. We reach a threshold above gate biases of −4.6 V, where the performance and stability become reduced due to device degradation occurring as a product of large-scale trap generation. The results not only suggest stress as an effective technique to enhance and reset charging properties but also offer insight on how standard industrial silicon devices can be harnessed for single charge transport applications.
Highlights
Introduction ce an us criThe ability to form quantum dots (QDs) through the fabrication of dedicated multi-gate devices as well as single impurity based structures has led numerous breakthroughs in quantum transport and quantum information processing schemes through manipulating individual charges [1, 2, 3, 4, 5, 6]
QDs originating from defects present in MOSFETs suffer from the inability to control aspects such as carrier number, size and coupling which are largely fixed by the poly-Si grains and interface defects that produce them [22, 23, 24, 25]
Successful attempts at mitigating the random nature by tuning disorder QDs for quantum information processing and memory purposes have been carried out, as well as taking advantage of the inherent randomness by demonstrating that the unique charging properties can be of use as a physically unclonable function (PUF)
Summary
The ability to form quantum dots (QDs) through the fabrication of dedicated multi-gate devices as well as single impurity based structures has led numerous breakthroughs in quantum transport and quantum information processing schemes through manipulating individual charges [1, 2, 3, 4, 5, 6]. The most significant challenge in this regard is that of device variability owing to random and uncontrollable charges in the vicinity of the QD, which are the leading causes of unpredictable behaviour This has meant exploring methods to improve the consistency and tunability of features that are essential to SHT function, such as charging energy (Ec ), capacitive couplings and activation energy (Ea ) [29]. One method is through the application of electrical stress in the form of a large gate bias Applying this technique draws parallels from the significant effort put forward historically into oxide reliability when down-scaling transistors in search of better performance, together with the development of resistive memory, where state switching is initiated as a consequence of voltage driven structural change within the Investigating stability and tunability of quantum dot transport in silicon MOSFETs via the application of electrical stress us cri oxide [30, 31].
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