摘要:
Method for conversion of a Flash memory cell on a first semiconductor device to a ROM memory cell in a second semiconductor device, the first and second semiconductor device each being arranged on a semiconductor substrate and each comprising an identical device portion and an identical wiring scheme for wiring the device portion to the Flash memory cell and to the ROM memory cell, respectively; the Flash memory cell being made in non-volatile memory technology and comprising an access transistor and a floating transistor, the floating transistor comprising a floating gate and a control gate; the ROM memory cell being made in a baseline technology and comprising a single gate transistor, which method includes manipulating a layout of at least one baseline mask as used in the baseline technology; the manipulation including: incorporating into the layout of the at least one baseline mask a layout of the Flash memory cell, and converting the layout of the Flash memory cell to a layout of one ROM memory cell by eliminating, from the at least one baseline mask, a layout for the floating transistor from the layout of the Flash memory cell and designating the layout of the access transistor of the Flash memory cell as a layout of the single gate transistor of the ROM memory cell.
摘要:
The invention relates in particular, though not exclusively, to an integrated circuit with an embedded non-volatile memory with floating gate (10). According to the invention, at least two poly layers of equal or at least substantially equal thickness are used for this device. The first poly layer, poly A, is for the floating gate (10) and for the gates (22) of NMOS and PMOS in the logic portion of the circuit. The second poly layer, poly B, serves exclusively for the control electrode (21) above the floating gate. If so desired, a third poly layer may be deposited for both the control electrode and the logic gates, so that the thicknesses of these electrodes, and thus their resistances, are given desired values. Problems like overetching and bridging during saliciding are prevented in that the control electrode and the logic gates have the same thickness.
摘要:
The invention provides a method of combining an EPROM (or EEPROM) with a standard CMOS process. After growing the gate oxide 9, a lightly doped polycrystalline or amorphous silicon layer 10, hereinafter referred to as poly I, is deposited. In this layer, the floating gate 13 of the memory cells is defined, while, outside the memory matrix, the surface remains covered with poly I. Subsequently, the source/drain implantation in the memory cells is carried out. The poly layer 10 situated outside the memory matrix is masked against this heavy implantation by the mask 11. Subsequently, a second poly layer can be provided from which the control gates of the memory cells are formed and which forms a coherent layer with the existing poly I layer outside the matrix. In a subsequent series of steps in a standard CMOS process, the n-ch MOSTs and p-ch MOSTs are provided, n-type gates 22 for the n-ch MOSTs and p-type gates 23 for the p-ch MOSTs being formed from the poly I layer.
摘要:
Method for conversion of a Flash memory cell on a first semiconductor device to a ROM memory cell in a second semiconductor device, the first and second semiconductor device each being arranged on a semiconductor substrate and each comprising an identical device portion and an identical wiring scheme for wiring the device portion to the Flash memory cell and to the ROM memory cell, respectively; the Flash memory cell being made in non-volatile memory technology and comprising an access transistor and a floating transistor, the floating transistor comprising a floating gate and a control gate; the ROM memory cell being made in a baseline technology and comprising a single gate transistor, which method includes manipulating a layout of at least one baseline mask as used in the baseline technology; the manipulation including: incorporating into the layout of the at least one baseline mask a layout of the Flash memory cell, and converting the layout of the Flash memory cell to a layout of one ROM memory cell by eliminating, from the at least one baseline mask, a layout for the floating transistor from the layout of the Flash memory cell and designating the layout of the access transistor of the Flash memory cell as a layout of the single gate transistor of the ROM memory cell.
摘要:
A semiconductor device comprises a semiconductor body (1) having a region (2) of a first conductivity type adjoining a surface (3) of the semiconductor body (1), which semiconductor body (1) is provided at the surface (3) with a non-volatile memory cell. The memory cell comprises a source (4) and a drain (5) of an opposite, second conductivity type provided in the semiconductor body (1), between which source (4) and drain (5) the surface (3) of the semiconductor body (1) is provided with a floating gate (6) and a select gate (10). The floating gate (6) and the select gate (10) both have a substantially flat surface portion (13) extending substantially parallel to the surface (3) of the semiconductor body (1) and side-wall portions (14) extending substantially transversely to the surface (3) of the semiconductor body (1). A control gate (7) is situated above the floating gate (6), and is capacitively coupled to the substantially flat surface portion (13) of the floating gate (6) and to at least the side-wall portions (14) of the floating gate (6) facing the source (4) and the drain (5). Moreover, the control gate (7) overlaps the select gate (10) and ends above the substantially flat surface portion (13) of the select gate (10).
摘要:
In the manufacture of integrated circuits with an embedded non-volatile memory, it is known to first provide the greater part of the memory and subsequently provide the CMOS logic in a second series of steps of a standard CMOS process. By virtue of this separation of process steps, it is possible to optimize the non-volatile memory substantially without degrading the logic. According to the invention, this process is further optimized in that, particularly for the periphery of the memory, and simultaneously with the memory transistors (21, 24, 27), transistors are manufactured which can cope with a higher voltage than the transistors of the logic. In the case of an EEPROM, each cell of the memory is provided with such a high-voltage transistor as a selection transistor (22, 24). Apart from the n-well implantation (5), high-voltage transistors of the p-channel are largely manufactured by means of the same process steps as the p-channel transistors in the logic, so that the number of process steps remains limited. By adding a single mask, the circuit may also be provided with a Flash or an OTP (One Time Programmable) memory.