Power semi-conductor module comprising: - at least one Insulated Gate Bipolar Transistor IGBT with a Gate forming a first electrode and an Emitter forming a second electrode, or - at least one Metal-Oxide-Semiconductor Field-Effect Transistor MOSFET with a Gate forming a first electrode and a Source forming a second electrode; wherein the first electrode comprises first electrode trenches and the second electrode comprises second electrode trenches; - a monitoring portion, wherein said first electrode and said monitoring portion are made in one piece comprising a polysilicon material (120, 131, 161), said monitoring portion being in electrical contact with the second electrode such that a leakage current flows between the first electrode and the second electrode in an operational state of the module; said monitoring portion having a location, a form, a size and a material composition selected together such that it has a variable resistance in function of its temperature during said operational state of said module, wherein the monitoring portion comprises at least one of the following: - a polysilicon layer covering continuously at least one first electrode trench and at least one second electrode trench and made in one piece with a polysilicon filling in said at least one first electrode trench and with a polysilicon filling in said at least one second electrode trench; - an extension part of polysilicon material between the polysilicon filling of a second electrode trench and a polysilicon material element of the first electrode in such a way to ensure an electric link between said two electrodes (11, 12); - a passage arranged through an oxide layer lining a wall of a first electrode trench of the first electrode. - at least one Insulated Gate Bipolar Transistor IGBT with a Gate forming a first electrode and an Emitter forming a second electrode, or - at least one Metal-Oxide-Semiconductor Field-Effect Transistor MOSFET with a Gate forming a first electrode and a Source forming a second electrode; wherein the first electrode comprises first electrode trenches and the second electrode comprises second electrode trenches; - a monitoring portion, wherein said first electrode and said monitoring portion are made in one piece comprising a polysilicon material (120, 131, 161), said monitoring portion being in electrical contact with the second electrode such that a leakage current flows between the first electrode and the second electrode in an operational state of the module; said monitoring portion having a location, a form, a size and a material composition selected together such that it has a variable resistance in function of its temperature during said operational state of said module, wherein the monitoring portion comprises at least one of the following: - a polysilicon layer covering continuously at least one first electrode trench and at least one second electrode trench and made in one piece with a polysilicon filling in said at least one first electrode trench and with a polysilicon filling in said at least one second electrode trench; - an extension part of polysilicon material between the polysilicon filling of a second electrode trench and a polysilicon material element of the first electrode in such a way to ensure an electric link between said two electrodes (11, 12); - a passage arranged through an oxide layer lining a wall of a first electrode trench of the first electrode. wherein said first electrode and said monitoring portion are made in one piece comprising a polysilicon material (120, 131, 161), said monitoring portion being in electrical contact with the second electrode such that a leakage current flows between the first electrode and the second electrode in an operational state of the module; said monitoring portion having a location, a form, a size and a material composition selected together such that it has a variable resistance in function of its temperature during said operational state of said module, wherein the monitoring portion comprises at least one of the following: - a polysilicon layer covering continuously at least one first electrode trench and at least one second electrode trench and made in one piece with a polysilicon filling in said at least one first electrode trench and with a polysilicon filling in said at least one second electrode trench; - an extension part of polysilicon material between the polysilicon filling of a second electrode trench and a polysilicon material element of the first electrode in such a way to ensure an electric link between said two electrodes (11, 12); - a passage arranged through an oxide layer lining a wall of a first electrode trench of the first electrode. - a polysilicon layer covering continuously at least one first electrode trench and at least one second electrode trench and made in one piece with a polysilicon filling in said at least one first electrode trench and with a polysilicon filling in said at least one second electrode trench; - an extension part of polysilicon material between the polysilicon filling of a second electrode trench and a polysilicon material element of the first electrode in such a way to ensure an electric link between said two electrodes (11, 12); - a passage arranged through an oxide layer lining a wall of a first electrode trench of the first electrode.