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针对纳米PMOS器件超浅结工艺面临的硼扩散问题,开展了预非晶化与激光退火和碳共注入结合的超浅结实验,通过透射式电子显微镜(TEM),二次离子质谱(SIMS),扩展电阻法(SRP)等测试对超浅结特性进行评估。结果表明,采用激光退火和碳共注入的方式可有效抑制硼扩散和减小结深。锗预非晶化后5 ke V,1×10~(15)/cm~2条件下注入的硼在激光退火(波长532 nm、脉冲宽度小于20 ns、能量密度0.25 J/cm~2)中的再扩散量非常小,退火后结深较注入结深仅增加6 nm,但激活率仅为24%。相同的硼掺杂条件下采用碳的共注入,常规快速热退火下的结深较未注碳样品减小49%,而且实现了84%的硼激活率。在单项实验基础上,进一步将预非晶化和碳共注入技术应用于纳米尺度器件制作,实验制备了亚50 nm PMOS器件,器件在Vdd=-1.2 V时的电流开关比大于104,亚阈值斜率为100 m V/dec,漏致势垒降低(DIBL)值为104 m V/V。
Aiming at the problem of boron diffusion in ultra-shallow junction process of nanostructured PMOS devices, an ultra-shallow junction experiment combining pre-amorphization with laser annealing and carbon co-implantation was carried out. Transmission electron microscopy (TEM), secondary ion mass spectrometry (SIMS) , Extended resistance method (SRP) and other tests to evaluate the super-shallow junction characteristics. The results show that the laser annealing and carbon injection can effectively inhibit the diffusion of boron and reduce the junction depth. The boron implanted at 5 ke V and 1 × 10 15 / cm 2 after pre-amorphization of germanium was annealed at 532 nm with a pulse width of less than 20 ns and an energy density of 0.25 J / cm 2 The amount of re-diffusion was very small. After annealing, the junction depth increased only 6 nm compared with the implant junction depth, but the activation rate was only 24%. In the same boron doping conditions, carbon co-implantation was used. The junction depth under conventional rapid thermal annealing was reduced by 49% compared with that of the un-injected carbon sample, and the boron activation rate of 84% was achieved. On the basis of single experiment, pre-amorphization and carbon co-implantation technology were further applied to nanoscale device fabrication. Sub-50 nm PMOS devices were fabricated experimentally. The current switching ratio of the device at Vdd = -1.2 V was above 104 and the subthreshold The slope is 100 mV / dec and the DIBL is 104 mV / V.