Structure and electrical properties of polysilicon films doped with ammonium tetraborate tetrahydrate

Here,p-type polysilicon films are fabricated by ex-situ doping method with ammonium tetraborate tetrahydrate(ATT)as the boron source,named ATT-pPoly.The effects of ATT on the properties of polysilicon films are comprehensively analyzed.The Raman spectra reveal that the ATT-pPoly film is composed of grain boundary and crystalline regions.The preferred orientation is the(111)direction.The grain size increases from 16−23 nm to 21−47 nm,by~70%on average.Comparing with other reported films,Hall measurements reveal that the ATT-pPoly film has a higher carrier concentration(>10^(20)cm^(−3))and higher carrier mobility(>30 cm2/(V·s)).The superior properties of the ATT-pPoly film are attributed to the heavy doping and improved grain size.Heavy doping property is proved by the mean sheet resistance(Rsheet,m)and distribution profile.The R_(sheet,m)decreases by more than 30%,and it can be further decreased by 90%if the annealing temperature or duration is increased.The boron concentration of ATT-pPoly film annealed at 950℃ for 45 min is~3×10^(20)cm^(−3),and the distribution is nearly the same,except near the surface.Besides,the standard deviation coefficient(σ)of Rsheet,m is less than 5.0%,which verifies the excellent uniformity of ATT-pPoly film.

The Expressions of P53, MDM2 in Trophoblasts of Spontaneous Abortion Mouse Model and the Relevant Researches

Objective: To explore the mRNA expression of the related genes of p53, MDM2, vascular endothelial growth factor (VEGF) and hypoxia inducible transcription factors-1 a (HIF-la) in villous samples of spontaneous abortion mouse models and normal pregnancy models, and to discuss the effect of p53, MDM2 on the growth of villous trophoblast cells. Methods: The abortion-prone CBAXDBA/2 matings were established as the model of spontaneous abortion and the non-abortion-prone CBAXBALB/c matings as the model of normal pregnancy. Applied q Real-time PCR method to detect the mRNA expression levels of p53, MDM2, VEGF and HIF-la in villous samples of spontaneous abortion mouse models and normal pregnancy models. Results: The relationship of the mRNA expression level of p53, MDM2, VEGF and HIF-la in vinous samples of spontaneous abortion mouse models: in the villous samples of spontaneous abortion mouse models, the expression of p53 was positively correlated with the expression of MDM2, HIF-la (r = 0.35;r = 0.63), and the relationship was significant (P = 0.01;P < 0.001);but negatively correlated to the expression of VEGF (r = ?0.30), and the relationship was significant (P = 0.03). The expression of MDM2 was positively correlated with the expression of HIF-la (r = 0.28), and the relationship was significant (P = 0.04);and negatively correlated with the expression of VEGF (r = ?0.08), but the relationship was not significant (P = 0.57). The expression of HIF-la was negatively correlated with the expression of VEGF (r = ?0.37), and the relationship was significant (P = 0.007). The relationship of the mRNA expression level of p53,MDM2, VEGF and HIF-1 a in vinous samples of normal pregnancy models: in the vinous samples of normal pregnancy models, the expression of p53 was positively correlated with the expression of MDM2, VEGF and HIF-la (r = 0. 31;r = 0. 48;r = 0. 67), and the relationship was significant (P = 0.03;P = 0.003;P < 0.001). The expression of MDM2 was positively correlated with the expression of VEGF (r = 0. 23), but the relationship was not significant (P = 0.11);and negatively correlated with the expression of HIF-la (r = ?0.03), but the relationship was not significant (P = 0.84). The expression of HIF-la was positively correlated with the expression of VEGF (r = 0. 35), and the relationship was significant (P = 0.01). Conclusion: angiogenesis reduces in villous samples of spontaneous abortion mouse model, P53 and MDM2 involve in angiogenesis in villous samples, unlikely p53, and MDM2 have effects on normal early pregnancy villous angiogenesis and when the cell DNA damages or hypoxia exacerbates, it can induce high expression of p53, MDM2, inhibit angiogenesis in villous samples in early pregnancy. P53, MDM2 generegulate villous trophoblast cell growth by adjusting expression of HIF-1a and VEGF gene, finally influences pregnancy.