Patent ID: 9691774
Date: 2017-06-27
CPC Classifications: G11C,H01L

Claim:
1. A method of forming a static random access memory (SRAM) cell, the method comprising: performing a first implantation process of a first dopant type to a first region of a semiconductor substrate, wherein the first region has a first concentration of the first dopant type; performing a second implantation process of the first dopant type to a second region of the semiconductor substrate, wherein the second region has a second concentration of the first dopant type that is greater than the first concentration; forming a first inverter that includes a first pull-up transistor and a first pull-down transistor over the semiconductor substrate, wherein the first pull-down transistor is formed over the first region such that the first pull-down transistor has a first threshold voltage; forming a port that includes a first pass-gate transistor, the port being coupled with the first inverter for data access, wherein the first pass-gate transistor is formed over the second region such that the first pass-gate transistor has a second threshold voltage that is greater than the first threshold voltage; and forming a read port coupled to the first inverter and different than the port, wherein the read port includes first and second read pull-down devices in parallel and first and second read pass-gate devices in parallel, wherein a gate of the first read pull-down device physically contacts a gate of the second read pull-down device, wherein a gate of the first read pass-gate device physically contacts a gate of the second read pass-gate device.