Flash cell with floating gate transistors formed using spacer technology
US8389356B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 10, 2011 |
| Grant date | Mar 5, 2013 |
| Priority date | — |
| Expiry date | Mar 10, 2031 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D64/035
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Methods for forming split gate flash cell structures provide for symmetrical cells that are immune to misalignment of the photoresist pattern when forming the control gates. Spacers are utilized to form the floating gates in the floating gate transistors used in the flash cells. The spacers may be oxide spacers used to mask a polysilicon layer that will form the floating gates or the spacers may be polysilicon spacers that will themselves form the floating gates. The inter-gate oxide of the floating gate transistors may be formed using HTO or may be deposited. Hard mask spacers are used in conjunction with the control gate photoresist patterning operation to control the size and configuration of the control gate and the channel length.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.