Extrinsic heat capacity in the metallic regime of heavily doped silicon and germanium

1978 ◽  
Vol 17 (6) ◽  
pp. 2631-2639 ◽  
Author(s):  
K. F. Berggren
Keyword(s):  
Heat Capacity ◽  
Doped Silicon ◽  
Heavily Doped ◽  
Silicon And Germanium

scholarly journals Temperature Characteristics of a Contour Mode MEMS AlN Piezoelectric Ring Resonator on SOI Substrate

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 143
Author(s):  
Sitao Fei ◽  
Hao Ren
Keyword(s):  
Quality Factor ◽  
Bottom Electrode ◽  
Temperature Stability ◽  
Cryogenic Cooling ◽  
Silicon On Insulator ◽  
Temperature Hysteresis ◽  
Sensing Applications ◽  
Doped Silicon ◽  
Heavily Doped ◽  
Contour Mode

As a result of their IC compatibility, high acoustic velocity, and high thermal conductivity, aluminum nitride (AlN) resonators have been studied extensively over the past two decades, and widely implemented for radio frequency (RF) and sensing applications. However, the temperature coefficient of frequency (TCF) of AlN is −25 ppm/°C, which is high and limits its RF and sensing application. In contrast, the TCF of heavily doped silicon is significantly lower than the TCF of AlN. As a result, this study uses an AlN contour mode ring type resonator with heavily doped silicon as its bottom electrode in order to reduce the TCF of an AlN resonator. A simple microfabrication process based on Silicon-on-Insulator (SOI) is presented. A thickness ratio of 20:1 was chosen for the silicon bottom electrode to the AlN layer in order to make the TCF of the resonator mainly dependent upon heavily doped silicon. A cryogenic cooling test down to 77 K and heating test up to 400 K showed that the resonant frequency of the AlN resonator changed linearly with temperature change; the TCF was shown to be −9.1 ppm/°C. The temperature hysteresis characteristic of the resonator was also measured, and the AlN resonator showed excellent temperature stability. The quality factor versus temperature characteristic was also studied between 77 K and 400 K. It was found that lower temperature resulted in a higher quality factor, and the quality factor increased by 56.43%, from 1291.4 at 300 K to 2020.2 at 77 K.

Free carrier absorption in heavily doped silicon layers

2004 ◽  
Vol 84 (13) ◽  
pp. 2265-2267 ◽  
Author(s):  
Joerg Isenberg ◽  
Wilhelm Warta
Keyword(s):  
Free Carrier ◽  
Free Carrier Absorption ◽  
Doped Silicon ◽  
Carrier Absorption ◽  
Heavily Doped
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