We have developed nanoscale double-gated field-effect-transistors for the study of electron states and transport properties of single deliberately implanted phosphorus donors. The devices provide a high-level of control of key parameters required for potential applications in nanoelectronics. For the donors, we resolve transitions corresponding to two charge states successively occupied by spin down and spin up electrons. The charging energies and the Lande g-factors are consistent with expectations for donors in gated nanostructures.

To expand the capabilities of semiconductor devices for new functions exploiting the quantum states of single donors or other impurity atoms requires a deterministic fabrication method. Ion implantation is a standard tool of the semiconductor industry and we have developed pathways to deterministic ion implantation to address this challenge. Although ion straggling limits the precision with which atoms can be positioned, for single atom devices it is possible to use post-implantation techniques to locate favourably placed atoms in devices for control and readout. However, large-scale devices will require improved precision. We examine here how the method of ion beam induced charge, already demonstrated for the deterministic ion implantation of 14 keV P donor atoms in silicon, can be used to implant a non-Poisson distribution of ions in silicon. Further, we demonstrate the method can be developed to higher precision by the incorporation of new deterministic ion implantation strategies that employ on-chip detectors with internal charge gain. In a silicon device we show a pulse height spectrum for 14 keV P ion impact that shows an internal gain of 3 that has the potential of allowing deterministic implantation of sub-14 keV P ions with reduced straggling.

No abstract

No abstract

No abstract

Deterministic doping is crucial for overcoming dopant number variability in present nano-scale devices and for exploiting single atom degrees of freedom. The development of deterministic doping schemes is required. Here, two approaches to the detection of single ion impact events in Si-based devices are reviewed. The first is via specialized PiN structures where ions are directed onto a target area around which a field effect transistor can be formed. The second approach involves monitoring the drain current modulation during ion irradiation. We investigate the detection of both high energy He + and 14 keV P + dopants. The stopping of these ions is dominated by ionization and nuclear collisions, respectively. The optimization of the implant energy for a particular device and post-implantation processing are also briefly considered. IntroductionRandom variations in the number and placement of dopants in classical metal-oxidesemiconductor field-effect-transistors (MOSFETs) are already major issues for CMOS devices operating at room temperature.[1] At 4 K quantum mechanical dependent functionalities have been observed in ultra-scaled MOSFETs with single adventitiously placed dopants. [2][3][4] In these devices the Bohr radius of a dopant atom is a significant fraction of the device size. Deterministic doping technologies aim to mitigate random variations in the doping while also allowing for the controlled fabrication of these ultrascaled devices. In addition, deterministic doping provides significant potential for solidstate quantum computers. [5][6][7][8] For example, the spin-dependent transport between a single 31 P atom and a single electron transistor has been proposed as a sensitive way to detect and control the P atom spin state.[9] Such an architecture requires the precise placement of a single P donor above which a shorted coplanar transmission line is deposited. This transmission line both carries microwave pulses that produce an oscillating magnetic field for local electron spin resonance and a dc bias as recently demonstrated.[10] Single ion implantation and detection has been reported by a number of groups. [11][12][13][14][15][16][17][18][19] These works are compared in Table I. The table shows the energy and type of implanted ion as well as the target type and detection scheme used. Low energy single dopant implantation into both micron-scale and nano-scale devices has been reported (indicated by the bold text in Table I). [11,15,19] Deterministic P implantation was achieved by the detection of the electron-hole (e-h) pairs created by the ion impact with an integrated PiN structure.[11] This scheme has resulted in a device where the timeresolved control and transfer of a single electron between two deterministically implanted P atoms was observed.[20] Other detection schemes are based on ion impact signals from secondary electrons [14,16,18] a These values represent the percentage of the total energy lost to ionization and nuclear recoils, respectively as calculated with SRIM. Additional energy los...

not Available.