以低壓化學氣相沉積法成長矽鍺碳三元化合物半導體薄膜

Abstract

本實驗以 Ge(SiMe3) 為前驅物, Si(111) 矽晶片為基材. 在 873 K - 973 K 之間以低壓化學氣相沉積法成長薄膜. 從 XRD 數據知在 923 K以 上所成長之薄膜晶形是面心立方結構,晶格常數 a 值約 0.441 -0.442 nm. 由 XPS 光譜分析中得知膜中 Si,Ge,C 三種元素是以均勻混合的鍵結 形式存在. 經 WDS 鑑定膜中 Si 的含量約 38 -43%, Ge 約 8 - 16% 而 C 的含量約 43 - 50% 之間,隨溫度的變化各元素的含量而有不同. 由數 據判知當沉積溫度在 923 K 以上薄膜是屬於碳化矽的晶形結構, 其中部 份的 Si 被 Ge 所取代經計算反應活化能約 40 - 52 kcal/mole, 據此研 判系統反應可能由矽鍺鍵的斷裂步驟所控制. 此外,以殘餘氣體分析儀作 反應副產物的偵測並以此結果推測反應可能途徑. Ge(SiMe3)4 was used as a single - source precursor to deposit thin films of alloys of germanium, silicon and carbon, Si1-x-y GexCy, by low pressure chemical vapor deposition on silicon subs trates at temperatures 873 - 973 K. X-ray diffraction studies cated that the films grown above 898 K were cubic phase (a= 0.441 - 0.442 nm). Infrared spectra of the films showed a major absorption near 783 cm-1. X-ray photoelectron spectra of acal thin film showed binding energies of Ge3d, Si2p, and C1s electrons at 30.0, 100.6 and 283.2 eV repectively. As determined by wavelength dispersive spectroscopy, x was 0.07 - 0.15 and y0.43 -0.5, indicating that the films contained 7 -15 % Ge. 38 - 43 % Si and 43 - 50 % C. At 973 K, C/(Si + Ge) ratio was 1. Based on these date, the films deposited above 898 K have acture of B-SiC With Ge atoms replacing some Si atoms in the lattice.