射頻橫向擴散金氧半場效電晶體之溫度效應探討

Temperature Effects on RF LDMOS Transistors

陳坤明 ； 黃國威 ； 胡心卉

《國家奈米元件實驗室奈米通訊》 17卷4期 (2010/12) Pp. 37-42

https://doi.org/10.29913/NDLC.201012.0007

摘要

本文探討射頻橫向擴散金氧半場效電晶體的溫度效應，並比較兩種不同佈局結構的元件，其電特性隨溫度之變化情形。研究中發現此兩種元件的截止頻率與最大震盪頻率皆隨溫度的上升而下降，截止頻率隨溫度的變化不僅受轉導值變化的影響，也與汲極電阻相關，藉由萃取元件的等效電路模型參數，我們找到了影響高頻參數的溫度行為的機制。在閘極電容特性研究方面，主要觀察到傳統魚骨形結構的元件，其閘極－源極／基體電容與閘極－汲極電容的峰值皆隨溫度的增加而減少；然而，方環形元件的閘極－汲極電容的峰值在高汲極偏壓時，反而隨溫度的增加而增加，此一現象與臨界電壓、類飽和電流及漂移區空乏電容的溫度相依性有關。

關鍵字

溫度 ； 橫向擴散金氧半場效電晶體 ； 截止頻率 ； 汲極電阻 ； 閘極電容 ； 類飽和電流

並列摘要

The temperature effects on the electrical characteristics of RF lateral diffused MOS (LDMOS) transistors are studied. Devices with different layout structures were fabricated using a 0.5 μm CMOSDMOS process. We found that both the cutoff frequency (f(subscript T))and the maximum oscillation frequency (f(subscript max)) decrease with increasing temperature. The variations of f(subscript T) with different temperatures are not only affected by the change in transconductance but also the drain resistance. We extracted the model parameters of the devices to explain this observation. For capacitance-voltage characterization, we observed that the peaks in gate-to-source/body capacitance (C(subscript GS)+C(subscript GB)) and gate-to-drain capacitance (C(subscript GD)) of fishbone devices decrease with increasing temperature. However, for ring structure, the peaks in CGD increase with increasing temperature at high drain voltages. This phenomenon can be explained by the temperature dependences of threshold voltage, quasi-saturation current and drift depletion capacitance.

並列關鍵字

Temperature ； LDMOS ； Cutoff Frequency ； Drain Resistance ； Gate Capacitance ； Quasi-Saturation Current