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基区Ge组分的加入可以改善SiGe HBT的直流特性、频率特性和噪声特性,但Ge组分及其分布对HBT热学特性的影响报道还很少.本文利用SILVACO半导体器件仿真工具,建立了多指SiGe HBT模型,对基区具有不同Ge组分梯度结构的SiGe HBTs的热学特性和电学特性的热稳定性进行了研究.研究发现,在Ge组分总量一定的条件下,随着Ge组分梯度的增大,器件的特征频率明显提高,增益β和特征频率fΤ随温度变化变弱,器件温度分布的均匀性变好,但增益变小;而基区均匀Ge组分(Ge组分梯度为零)的HBT的增益较大,但随温度的变化较大,器件温度分布的均匀性也较差.在此基础上,将基区Ge组分均匀分布和Ge组分缓变分布相结合,提出了兼顾器件热学特性、增益特性和频率特性的新型基区Ge组分分布-分段分布结构.结果表明,相比于基区Ge组分均匀分布的器件,新器件温度明显降低;β和fΤ保持了较高的值,且随温度的变化也较小,显示了新结构器件的优越性.这些结果对HBT的热学设计具有重要的参考意义,是对SiGe HBT性能研究的一个补充.
The addition of base Ge component can improve the DC characteristics, frequency characteristics and noise characteristics of SiGe HBT, but the influence of Ge composition and its distribution on the thermal properties of HBT is still poor.In this paper, SILVACO semiconductor device simulation tool was used to establish Refers to the SiGe HBT model and studies the thermal and electrical properties of SiGe HBTs with different Ge composition gradient in the base region.The results show that with the total amount of Ge component, As the gradient increases, the characteristic frequency of the device increases obviously, the gain β and the characteristic frequency f T become weaker with temperature, the uniformity of the device temperature distribution becomes better, but the gain becomes smaller. However, the average Ge component (Ge component Gradient of zero) HBT gain larger, but with temperature changes larger, the temperature uniformity of the device is also poor.On this basis, the Ge base component Ge uniform distribution and Ge component slowly changing phase A novel Ge-based component distribution-segmented distribution structure that takes into account the thermal, gain and frequency characteristics of the device is proposed.The results show that the temperature of the new device is significantly lower than that of the Ge component with uniform distribution in the base region, β and fT keep higher values , And the change with temperature is also small, showing the superiority of the new structural devices.These results have important reference meaning for the thermal design of HBT, which is a supplement to the research of SiGe HBT performance.