Then DC characteristics of the transistor are described by using a mathematical model the calculated current gain is obtained and an optimal design scheme of a Bi-CMOS npa bipolar transistor fully-compatible with CMOS process is presented .

然后，建立了分析计算 晶体管 直流特性的数学模型，并分析计算了工艺参数、器件结构对器件性能的影响，给出了CMOS工艺全兼容的 Bi-CMOS双极型npn晶体管的最佳设计方案。

It is shown that the new transistor has more uniform characteristics of current gain at low current level and an excellent low-frequency noise figure so that it is a promising low noise device at low frequency with simpler processes .

实验结果表明， 漂洗 发射 极 晶体管的小 电流 增益均匀性好，具有良好的低频噪声特性，是一种工艺比较简化，性能较好的低频低噪声器件。

Based on the theoretical model a new type of the transistor with low temperature coefficient of the current gain has been manufactured successfully .

据此理论模型研制成功了 电流 增益温度特性优良的 中小 功率 晶体管系列。

Meanwhile polysilicon transistor has positive temperature coefficient of current gain . The transistor has the same temperature property with bulk silicon with a smaller change of current gain when temperature is varying . 2 .

多晶硅 三极 管 的 电流 增益具有正温度系数，大电流下的电流增益随温度的变化比小电流情况小，该三极管具有和体硅相同的温度特性。