摘要:
A method is provided of manufacturing a P-channel native MOS transistor in a circuit integrated on a semiconductor which also includes a matrix of non-volatile memory cells of the floating gate type with two polysilicon levels having an interpoly dielectric layer sandwiched between the two polysilicon levels. The method has the following steps: (1) masking and defining active areas of the discrete integrated devices; (2) masking and defining the first polysilicon level using a Poly1 mask; and (3) masking and defining an intermediate dielectric layer using a matrix mask. The length of the native threshold channel of the native transistor is defined by means of the matrix mask and by etching away the interpoly dielectric layer. A subsequent step of masking and defining the second polysilicon level provides for the use of a Poly2 mask which extends the active area of the transistor with a greater width than the previous mask in order to enable, by subsequent etching, the two polysilicon levels to overlap in self-alignment over the channel region.
摘要:
A method of manufacturing a semiconductor virtual ground memory device having a matrix of floating gate memory cells formed on a semiconductor substrate with a plurality of continuous bit lines extending across the substrate as discrete parallel stripes. The device also includes a circuit portion for selection transistors and decode and address circuit portions having P-channel and N-channel MOS transistors. According to the method, N-wells are formed in at least one substrate portion to accommodate the P-channel transistors, active areas of all transistors are defined using a screening mask, and then an isolation layer is grown through the apertures of the screening mask. The screening mask is not open over the matrix region of the memory cells.