在本文中，我們提出了二種改善熱穩定性的方法，第一，我們成功研製了以InGaAsN(Sb)為通道的高電子移動率電晶體，Sb常常被應用在成長 InGaAsN/GaAs 量子井時通入，可當成一種類似活化劑的作用，其優點是可以抑制其三維(3-D)的表面成長，使其維持在二維(2-D)的表面成長，使得InGaAsN 成長時所產生的Dislocation 大為減少，材料成長品質大為提升。
實驗結果顯示，高電子移動率電晶體的結構中使用新式的InGaAsN(Sb)當通道，可以有效的改善元件的通道結構，並且加強載子的侷限能力。因此，InGaAsN(Sb) HEMT和 InGaAsN HEMT相比，擁有較佳的直流特性與熱穩定度。
在室溫下，由於在通道加入Sb，其最大異質轉導值從74.1 mS/mm增加為109 mS/mm。電流驅動能力IDSS原本是70 mA/mm，也因為使用InGaAsN(Sb)當通道而提高至87 mA/mm。而當溫度從300K變化至480K時，InGaAsN HEMT的臨界電壓變化率是-1.07 mV/K，而InGaAsN(Sb) HEMT的變化率降低至-0.807 mV/K。
第二，我們在InGaAs(Sb) HEMT中，運用doped channel 的方式，期望能夠改善它的熱穩定性，由於doped channel 隨著溫度上升受通道中載子濃度上升的影響較小，因此可以使元件較不受溫度的影響。
實驗結果顯示，雖然doped channel InGaAs(Sb) HEMT由於doped channel造成mobility下降的關係，使得最大異質轉導值及電流驅動能力IDSS變小，但是因為doped channel 通道中的載子分佈較為均勻，使得通道會被緩慢地空乏，所以讓GVS從1.2 V增加至1.63 V。此外，還獲得極佳的熱穩定性，當溫度從300K變化至480K時，InGaAs(Sb) HEMT的臨界電壓變化率是-1.54 mV/K，而doped channel InGaAs(Sb) HEMT的變化率降低至-0.70 mV/K。

We suggest two ways to improve thermal stability in this study. First, a high electron-mobility transistor (HEMT) by using a dilute antimony InGaAsN(Sb) channel has been successfully investigated. The advantages by incorporating the surfactant-like Sb atoms during growth of InGaAsN/GaAs quantum well (QW) consist of the suppression of the three-dimensional growth and the improved crystalline quality.
The experimental results of the studied device by using a dilute antimony InGaAsN(Sb) channel can improve the channel layer quality and enhance carrier confinement. Thus, compared with InGaAsN HEMT, InGaAsN(Sb) HEMT has better dc characteristics and highly thermal stability.
The values of the gm, max and the drain-source current density (IDSS), are 109 (66.4) mS/mm and 87 (70) mA/mm at room temperature for the studied HEMT with (without) adding the Sb atoms into the InGaAsN channel, respectively. Significant improvement in gm and IDSS values has been successfully achieved by employing the dilute antimony channel. The thermal threshold coefficient (Vth/T) is -0.807 (-1.07) mV/K for the InGaAsN(Sb) HEMT and the conventional InGaAsN HEMT at 300 (450)K, respectively.
Second, we apply doped channel structure to the InGaAs(Sb) HEMT in order to future improve thermal stability. When temperature rises, the device performance is affected slightly by increasing carrier concentration in the channel. Thus, the degradation of device performance at high temperature is insignificant.
Although the studied device can not improve the peak extrinsic transconductance and drain-to-source saturation current density due to mobility decreasing, the doped channel InGaAs(Sb) HFET demonstrates the great gate-voltage swing (GVS) value is 1.63 V compared with that is 1.2 V of InGaAs(Sb) HEMT. The better GVS characteristic of doped channel InGaAs(Sb) HFET is owing to the carriers have been uniformly distributed in the channel and the channel has been depleted slowly. Besides, the present doped channel device also achieves superior stable thermal characteristics. The thermal threshold coefficient (Vth/T) is -0.70 (-1.54) mV/K for the InGaAs(Sb) doped channel HFET and the InGaAs(Sb) HEMT at 300 (450)K, respectively.

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