| Autor: |
Gurary, Alex, Belousov, Mikhail, Bodycomb, Jeff, Boguslavskiy, Vadim, Ramer, Jeff, Hoffman, Richard |
| Předmět: |
|
| Zdroj: |
AIP Conference Proceedings; 2003, Vol. 684 Issue 1, p843-848, 6p |
| Abstrakt: |
Deposition processes for many Compound Semiconductors Devices (such as InGaAsP/InP infrared laser diodes or InGaP/GaAs heterojunction bipolar transistors) are extremely temperature sensitive with temperature windows as small as 2 °C to 3 °C. Requirements for process temperature repeatability can be less than ± 0.25 °C at temperatures in the range ∼ 650 °C to 750 °C which significantly exceed typical requirements for the silicon industry. While temperature control is a vital requirement for growing reproducible structures, wafer temperatures can deviate significantly from those measured by conventional techniques such as close proximity thermocouples or optical pyrometers. Elements (such as susceptor, wafer carrier and gaps filled by low pressure gas) located between the thermocouple and the wafer lead to measurement errors, particularly when the environment of the chamber changes such as during gas switching. Optical pyrometer measurements may have an error up to 100 °C due to emissivity oscillations during deposition of the thin epitaxial layers. To overcome these problems, Emcore recently developed an Emissivity Compensated Pyrometer known as RealTemp® for use in multi-wafer Rotating Disk Reactors, which provides a real-time accurate measurement of the wafer surface temperature during growth. RealTemp® is a device that combines a reflectometer (for accurate, real-time emissivity measurements) and a pyrometer (utilizing measured emissivity for accurate temperature calculations). We also use this more accurate temperature data for real-time wafer surface temperature control. In our presentation we will report on the basic metrological parameters of the developed RealTemp® pyrometer including the effect of the target emissivity on the accuracy of the temperature measurements. We will describe a high-speed algorithm that separates temperature measurements on the semiconductor wafers from measurements on the carrier used to hold wafers during deposition processes. Also we will describe experiments performed to verify the accuracy of the temperature measurements using emissivity compensated pyrometry. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
