Title :
Fabrication of microcrystalline silicon TFTs using a high-density plasma approach
Author :
Krishnan, A.T. ; Sanghoon Bae ; Fonash, S.J.
Author_Institution :
Texas Instrum. Inc., Dallas, TX, USA
Abstract :
N-channel microcrystalline silicon (mc-Si) thin film transistors (TFTs) were fabricated using a high density plasma (HDP) approach. An electron cyclotron resonance (ECR) plasma source was employed to deposit all of the thin film materials needed for the transistor; that is, intrinsic mc-Si, n-type mc-Si, and dielectric silicon dioxide were grown with the ECR high density plasmas and the deposition rates for these films were in the range of 120-150 /spl Aring//min. The substrate temperatures during these depositions were maintained below 285/spl deg/C. To complete the fabrication of these TFTs, we used only two masks with one alignment. After 1 h annealing under forming gas atmosphere, the mc-Si TFTs perform with linear field effect mobility of 12 cm2/V-s, on/off ratio of 106, subthreshold swing of 0.3 V/decade, off-current of 4×10/sup -13/ A/μm and threshold voltage of 5 V.
Keywords :
annealing; carrier mobility; elemental semiconductors; plasma CVD; semiconductor device measurement; silicon; thin film transistors; 1 hour; 285 C; 5 V; SiO/sub 2/-Si-SiN; annealing; deposition rates; dielectric silicon dioxide; electron cyclotron resonance plasma source; forming gas atmosphere; high-density plasma approach; linear field effect mobility; masks; microcrystalline silicon TFTs; off-current; on/off ratio; substrate temperature; subthreshold swing; thin film materials deposition; thin film transistors; threshold voltage; Dielectric substrates; Dielectric thin films; Electrons; Fabrication; Plasma density; Plasma materials processing; Plasma sources; Plasma temperature; Silicon; Thin film transistors;
Journal_Title :
Electron Device Letters, IEEE
