SUPRESSION OF SHORT-CHANNEL EFFECT IN MOSFET WITH UV EXCIMER LASER DOPING

提出了用激光CVD沉积掺杂源和激光熔融引入掺杂剂的两步激光掺杂技术，以形成表面浓度很高的很浅的结。从方块电阻和掺杂分布两个方面详细研究了该技术的特性。通过改变掺杂过程中的激光脉冲数目和硅熔化过程中的激光脉冲数目，可以在很大范围内精确地控制方块电阻，可以形成非常浅的(0.1微米)结，具有很高的表面浓度(1×10^&lt；20&gt；cm^3)，这表明该技术适用于形成MOSFET的源区和漏区。源极层和漏极层是使用两步掺杂形成的。除LPCVD栅氧化层在450℃下沉积外，其余器件均在室温下进行工艺处理，获得了通断比为7、场效应空穴迁移率为145 cm~2/vs的高质量MOSFET。

Two-step laser doping technique consisting of the deposition of dopant source by laser CVD and the introduction of dopant by laser melt was proposed to form very shallow junctions with very high surface concentrations. Characteristics of this technique were investigated in details in terms of sheet resistance and doping profiles. Changing the number of irradiated laser pulse in the dopant deposition process and the number of laser pulse in the silicon melting process, sheet resistance can be controlled precisely in the wide range.Very shallow (0.1mum) junctions with very high surface concentration (1x10^<20>cm^3) can be formed, indicating that this technique is applicable to form the source and drain region of MOSFETs.Using the two-step doping with excimer laser, p-channel MOSFETs were fabricated on SOS (silicon on sapphire) . Source and drain layrs were formed using two-step doping. Devices were processed at room temperature except for the LPCVD gate oxide deposited at 450C.High-quality MOSFETs were fabricated with on/off ratio of 7 and a field effect hole mobility of 145 cm^2/Vs