Abstract: An amplifier circuit comprises a measurement path with an amplifier (1) for providing an output voltage (Vout) depending on a measuring current (Ipd) with a first and a second amplifier input (11, 12), and an amplifier output (13). A return path of the amplifier circuit comprises a first filter (2), an auxiliary amplifier (3) and a second filter (4). In this case, the first filter (2) is designed to filter a DC voltage from the output voltage (Vout) and is connected to the amplifier output (13). The auxiliary amplifier (3) serves to convert an input voltage (Vfil) into an output current (Ifil) and has a first and a second auxiliary amplifier input (31, 32) and an auxiliary amplifier output (33). In this case, the first auxiliary amplifier input (31) is connected to the first filter (2). The second filter (4) is designed to filter noise from the output current (Ifil) and couples the auxiliary amplifier output (33) to the first amplifier input (11).

Abstract: A method for manufacturing a semiconductor body with a trench comprises the steps of etching the trench (11) in the semiconductor body (10) and forming a silicon oxide layer (12) on at least one side wall (14) of the trench (11) and on the bottom (15) of the trench (11) by means of thermal oxidation. Furthermore, the silicon oxide layer (12) on the bottom (15) of the trench (11) is removed and the trench (11) is filled with polysilicon that forms a polysilicon body (13).