Microchannel gate temperature analysis
Photoemission spectra of a GaAs gate material of a metal semiconductor field effect transistor (MESFET) were analyzed to nondestructively assess the submicron-size local gate temperature. Utilizing the micromanipulator, the laser beam was precisely adjusted to probe the exact position of the device gate. The emission spectral bands due to the interaction among photons, free excitons and impurity bound excitons in GaAs gate materials were measured and identified both at 299.1 K and 84.8 K. The shift of the band was found to be 16.30 meV for the free excitons when the device was not powered, while the band shift of the gate was 7.38 meV when the device was powered at 84.8 K. Simple first order calculations based on the theory of temperature shift of the bound excitons, predicts an inversely proportional relationship between the emission bandshift and temperature. Measurements using this technique found an increase of 97.0 K.