发明名称 |
Systems and methods of non-volatile memory sensing including selective/differential threshold voltage features |
摘要 |
Systems and methods are disclosed for providing selective threshold voltage characteristics via use of MOS transistors having differential threshold voltages. In one exemplary embodiment, there is provided a metal oxide semiconductor device comprising a substrate of semiconductor material having a source region, a drain region and a channel region therebetween, an insulating layer over the channel region, and a gate portion of the insulating layer. Moreover, with regard to the device, the shape of the insulating layer and/or the shape or implantation of a junction region are of varied dimension as between the gate-to-drain and gate-to-source junctions to provide differential threshold voltages between them. |
申请公布号 |
US9548087(B2) |
申请公布日期 |
2017.01.17 |
申请号 |
US201414229763 |
申请日期 |
2014.03.28 |
申请人 |
Silicon Storage Technology, Inc. |
发明人 |
Tran Hieu Van;Saha Samar |
分类号 |
G11C7/06;G11C16/28;H01L21/28;H01L21/8234;H01L21/8238;H01L29/10;H01L29/423;H01L29/66;H01L29/78;H01L29/792 |
主分类号 |
G11C7/06 |
代理机构 |
DLA Piper LLP (US) |
代理人 |
DLA Piper LLP (US) |
主权项 |
1. A sensing circuit for a flash memory device comprising:
a reference column including a reference voltage node, a reference memory cell, a first differential threshold PMOS transistor that is diode-connected and has a drain connected to the reference voltage node, and a first differential threshold NMOS transistor having a drain connected to the reference voltage node; circuitry comprising a comparator that includes a second differential threshold NMOS transistor having a gate connected to a reference voltage line and a source connected to a first node, a third differential threshold NMOS transistor having a drain connected to the first node, a second differential threshold PMOS transistor that is diode-connected and has a drain connected to a second node, a third differential threshold PMOS transistor having a gate connected to the second node and a drain connected to a third node, a fourth differential threshold NMOS transistor having a source connected to the first node, a fourth differential threshold PMOS transistor having a gate connected to the third node and a drain connected to an output node, and a fifth differential threshold NMOS transistor having a drain connected to the output node, wherein gates of the fourth and fifth differential threshold NMOS transistors are connected to a common control line; wherein one or more of the differential threshold transistors are transistors that each have a gate-to-source threshold voltage that differs from a gate-to-drain threshold voltage; and wherein one or more of the differential threshold transistors comprises:
a substrate of semiconductor material of a first conductivity type;a first region and a second region in the substrate, wherein the first and second regions are of a second conductivity type and spaced apart from each other defining a channel region therebetween;an insulating layer disposed over the channel region of the substrate, wherein the insulating layer comprises opposed insulating portions including a first insulating portion adjacent the first region and a second insulating portion adjacent the second region; anda gate portion above the insulating layer;wherein each insulating portion characterizes a threshold voltage between the gate and the first region or the second region adjacent each insulating portion; andwherein the first insulating portion is fabricated with varying dimension including a first thickness different than a second thickness of the second insulating portion to provide a first threshold voltage that differs from a second threshold voltage associated with the opposed insulating portion. |
地址 |
San Jose CA US |