Apparatus and methods for thermally processing undoped and lightly doped substrates without pre-heating
US7482254B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Sep 26, 2005 |
| Grant date | Jan 27, 2009 |
| Priority date | — |
| Expiry date | Aug 14, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/67115
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Apparatus for and methods of thermally processing undoped or lightly doped semiconductor wafers (30) that typically are not very absorptive of an annealing radiation beam (14) are disclosed. The apparatus (10) uses a relatively low power activating radiation beam (240) with a photon energy greater than the bandgap energy of the semiconductor substrate in order to generate free carriers (315) at and near the substrate surface (32). The free carriers so generated enhance the absorption by the substrate surface of the longer wavelength annealing radiation beam. The annealing radiation beam is thus able to rapidly heat the substrate surface and permit subsequent rapid cooling to obtain, for example, a high level of electrical activity (activation) of dopants (310) formed therein. The invention obviates the need to pre-heat the substrate in order to increase absorption of the annealing radiation beam when performing thermal processing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.