The invention discloses a process for manufacturing a radiation detector for detecting e.g. 200 eV electrons. This makes the detector suited for e.g. use in an Scanning Electron Microscope. The detector is a PIN photodiode with a thin layer of pure boron connected to the p+-diffusion layer. The boron layer is connected to an electrode with an aluminium grid to form a path of low electrical resistance between each given point of the boron layer and the electrode. The invention addresses forming the aluminium grid on the boron layer without damaging the boron layer. To that end the grid of aluminium is formed by covering the boron layer completely with a layer of aluminium and then removing part of the layer of aluminium by etching, the etching comprising a first step (304) of dry etching, the step of dry etching defining the grid but leaving a thin layer of aluminium on the part of the boron layer to be exposed, followed by a second step (308) of wet etching, the step of wet etching completely removing the aluminium from the part of the boron layer to be exposed.
|Patent number||US8450820 B2|
|Publication status||Published - 28 May 2013|