Abstract: A charged-particle source for generating a charged-particle comprises a sequence of electrodes, including an emitter electrode with an emitter surface, a counter electrode held at an electrostatic voltage with respect to the emitter electrode at a sign opposite to that of the electrically charged particles, and one or more adjustment electrodes surrounding the source space between the emitter electrode and the counter electrode. These electrodes have a basic overall rotational symmetry along a central axis, with the exception of one or more steering electrodes which is an electrode which interrupts the radial axial-symmetry of the electric potential of the source, for instance tilted or shifted to an eccentric position or orientation, configured to force unintended, secondary charged particles away from the emission surface.

Abstract: A charged-particle source for generating a charged-particle comprises a sequence of electrodes, including an emitter electrode with an emitter surface, a counter electrode held at an electrostatic voltage with respect to the emitter electrode at a sign opposite to that of the electrically charged particles, and one or more adjustment electrodes surrounding the source space between the emitter electrode and the counter electrode. These electrodes have a basic overall rotational symmetry along a central axis, with the exception of one or more steering electrodes which is an electrode which interrupts the radial axial-symmetry of the electric potential of the source, for instance tilted or shifted to an eccentric position or orientation, configured to force unintended, secondary charged particles away from the emission surface.

Abstract: A charged-particle source for emission of electrons or other electrically charged particles comprises, located between the emitter electrode having an emitter surface and a counter electrode, at least two adjustment electrodes; a pressure regulator device is configured to control the gas pressure in the source space at a pre-defined pressure value. In a first cleaning mode of the particle source, applying a voltage between the emitter and counter electrodes directs gas particles towards the counter electrode, generating secondary electrons which ionize particles of the gas in the source space, and electrostatic potentials are applied to at least some of the adjustment electrodes, generating an electric field directing the ionized gas particles onto the emitter surface.

Abstract: A charged-particle source for emission of electrons or other electrically charged particles comprises, located between the emitter electrode having an emitter surface and a counter electrode, at least two adjustment electrodes; a pressure regulator device is configured to control the gas pressure in the source space at a pre-defined pressure value. In a first cleaning mode of the particle source, applying a voltage between the emitter and counter electrodes directs gas particles towards the counter electrode, generating secondary electrons which ionize particles of the gas in the source space, and electrostatic potentials are applied to at least some of the adjustment electrodes, generating an electric field directing the ionized gas particles onto the emitter surface.

Abstract: A type III-V semiconductor substrate is provided. Semiconductor material is removed from the type III-V semiconductor substrate such that the type III-V semiconductor substrate comprises one or more alignment features extending away from a main lateral surface. Each of the alignment features includes a first lateral surface that is vertically offset from the main lateral surface, and first and second vertical sidewalls that extend between the first lateral surface and the main lateral surface. An epitaxy blocker is formed on the first and second vertical sidewalls of each alignment feature. A type III-V semiconductor regrown layer is epitaxially grown on a portion of the semiconductor wafer that includes the one or more alignment features. The epitaxy blocker prevents the type III-V semiconductor regrown layer from forming on the first and second vertical sidewalls of the one or more alignment features.

Abstract: A type III-V semiconductor substrate is provided. Semiconductor material is removed from the type III-V semiconductor substrate such that the type III-V semiconductor substrate comprises one or more alignment features extending away from a main lateral surface. Each of the alignment features includes a first lateral surface that is vertically offset from the main lateral surface, and first and second vertical sidewalls that extend between the first lateral surface and the main lateral surface. An epitaxy blocker is formed on the first and second vertical sidewalls of each alignment feature. A type III-V semiconductor regrown layer is epitaxially grown on a portion of the semiconductor wafer that includes the one or more alignment features. The epitaxy blocker prevents the type III-V semiconductor regrown layer from forming on the first and second vertical sidewalls of the one or more alignment features.