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US 12,660,365 B2Granted
Method for manufacturing, by differentiated electrochemical porosification, a growth substrate including mesas having various porosification levels
AssigneeCommissariat A L'energie Atomique Et Aux Energies Alternatives
InventorsLudovic Dupre, Amélie Dussaigne, Carole Pernel, Fabian Rol
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Abstract
A method for manufacturing a growth substrate, including producing mesas based on GaN having various porosification levels, implementing differentiated steps of electrochemical porosification, non-photoassisted and photoassisted, of various portions of the mesas.
Claims13
A method for manufacturing a growth substrate configured to produce by epitaxy a matrix of diodes based on InGaN, including the following steps:
- providing a crystalline stack based on GaN, including:
- a doped bottom layer;
- and a top layer produced from Inx2Ga1-x2N with x2>0, resting on and in contact with the doped bottom layer;
- where:
- the doped bottom layer has a proportion of indium x1≥0 predefined so that it is non-adsorbent of an illumination light radiation having a predefined central wavelength, and the top layer has a proportion of indium x2>0 predefined so that it is absorbent of the illumination light radiation;
- the doped bottom layer has a doping level predefined so that it is porosifiable at an electrical voltage of predefined value VECE, and the top layer (24) has a doping level predefined so that it is non-porosifiable at the predefined electrical voltage VECE;
- producing mesas M(i), with i ranging from 0 to 2, by localised etching of the top layer to form top portions of mesas and of at least part of the doped bottom layer to form bottom portions of mesas;
- then
- depositing an encapsulation layer made of an electrically insulating material, covering at least one mesa denoted M(0), so that said mesa M(0) is not porosified during an electrochemical porosification of mesas denoted M(1) and M(2);
- then
- electrochemical porosification of the bottom and top portions of at least one mesa M(2) by:
- photoassisted porosification of the top portion of the mesa M(2) by emission of the illumination light radiation;
- and non-photoassisted of the bottom portion of the mesa M(2) by applying the electrical voltage of value VECE;
- electrochemical porosification of only one of the bottom and top portions of at least one mesa M(1) by:
- photoassisted porosification of the top portion of the mesa M(1) during that of the top portion of the mesa M(2);
- or non-photoassisted of the bottom portion of the mesa M(1) during that of the bottom portion of the mesa M(2);
- at least partial removal of the encapsulation layer, so as to make free a top surface of the mesa M(0).
14 more elements
A growth substrate configured to produce by epitaxy a matrix of diodes based on InGaN, including:
- a support layer;
- mesas M(i), with i ranging from 0 to 2, made from crystalline GaN, resting on the support layer, and each including:
- a doped bottom portion having a proportion of indium x1≥0;
- and a top portion made from Inx2Ga1-x2N with a proportion of indium x2>x1 and having a doping level less than that of the bottom portion, and resting on and in contact with the bottom portion;
- the mesas being configured so that:
- the bottom and top portions of the mesa M(0) are non-porous;
- only one portion among the bottom and top portions of the mesa M(1) is porous;
- the bottom and top portions of the mesa M(2) are porous.
5 more elements
Dependencies are inferred from the claim text.