純鍺基板是下一代MOSFETs的前瞻通道材料，然而鍺半導體材料製程也存在許多困難，在高溫製程下鍺氧化層容易揮發及水解。因此介面工程一直是鍺金氧半電晶體製程中的關鍵問題，得到一層品質良好的介面層相當重要。本論文研究以ALD水氣電漿做為沉積介面層主要製程，為了增加其GeO2介面層Ge4+的含量，改變製程腔體溫度，探討介面層成長溫度之影響。接著透過有無氫氣電漿對介面層進行處理，搭配低溫微波系統或爐管FGA下退火，找出較佳的退火處理，降低製程熱預算，提升mobility。最後，希望得到較低的閘極漏電流，分別使用NH3、N2、CF4電漿對介面層表面進行處理，產生極性化合物(GeON)並搭配微波退火，達到局部活化的效果，以得到最佳的介面處理方式提升元件特性。
第一部分使用ALD通以水氣電漿方式形成GeO2作為介面層，其中分別使用不同製程溫度來成長介面層，分別為350℃、250℃、100℃。使得基板有足夠溫度讓水氣電漿和鍺完全反應產生GeO2，並增加Ge4+含量，探討不同溫度下成長之介面層品質。低溫100℃下成長介面層，品質最為鬆散閘極漏電流大。中溫250℃下成長介面層會是一個最佳的溫度，有最小的EOT 5.1 Å和最低的閘極漏電密度5.1 x 10-3 A/cm2。
第二部分討論有無氫氣電漿對介面層進行處理，搭配低溫微波系統或一般爐管FGA下退火。接續上一章最佳的介面層成長溫度，實驗結果可以看出，氫氣電漿對介面層處理可以有效的降低EOT，而無氫氣電漿處理搭配低溫微波加熱系統退火有較佳的特性。載子遷移率方面可以將phonon scattering的效應降至最低，因此得到最高的載子遷移率575 cm2/V-sec，和最大的導通電流。
第三部分使用NH3、N2、CF4電漿對介面層表面進行處理，並搭配前兩章最佳製程條件，實驗結果可以看到NH3電漿處理搭配微波退火，可以氮化介面層GeO2鍵結成極性分子GeON。經由微波退火局部加熱增加介面層中Ge4+含量比例，Ge4+增加表示介面層內含有較多能隙大的GeO2，大幅降低閘極漏電流至1.88 x 10-5 A/cm2。而介面層上方GeON可避免IL和high-k兩層混合，降低因high-k離子極化產生的聲子散射(Phonon scattering)，載子移動率增加至588 cm2/V-sec，所以有最大的導通電流和On/Off ratio 3.4個數量級。本實驗發現含有氮之電漿處理介面層搭配低溫微波退火可以有效降低元件閘極漏電流。

Germanium (Ge) is proposed as promising channel material for next generation metal oxide semiconductor field effect transistor (MOSFETs), because electron and hole mobility are about two and four times higher than Si respectively. However, there are many challenges for applying Ge as channel material. Ge oxide is easily volatilized and hydrolyzed at high temperature. The interface engineering is always one of key factors in the semiconductor processes to achieve high quality GeO2 interfacial layer of Ge MOSFET. A GeO2 formed with H2O plasma in ALD chamber is applied to serve as main IL. Formation temperature of H2O plasma grown GeO2 IL, w/ or w/o H2 plasma and microwave annealing (MWA) or forming gas annealing (FGA), and w/ or w/o NH3, N2, CH4 plasma with MWA treatments on electrical characteristics of Ge pMOSFET are studied in this thesis.
In the first part, GeO2 IL was formed by H2O plasma in ALD chamber at various temperatures, including 350, 250, and 100℃. The interface quality of IL grown at low temperature (100℃) is poor, resulting in high gate leakage density (JG). A suitable temperature for growing GeO2 IL is at 250℃. The JG is reduced to 5.1 x 10-3 A/cm2 at low EOT of 5.1 Å.
In the second part, IL w/ or w/o hydrogen plasma treatment and together with MWA or FGA at low temperature were applied to fabricate Ge MOSFET. Base on the first part, the optimal IL grown temperature is 250℃. Results show that the EOT value can be effectively reduced by hydrogen plasma treatment. Peak hole mobility of ~575 cm2/V-sec at EOT value of 0.73 nm is achieved for sample w/o hydrogen plasma and w/ MWA treatment, which can further increase ID on current of due to reduced remote phonon scattering.
GeO2 IL grown at 250℃ and plasma treated IL with MWA were applied in the third part, the GeO2 IL was treated with NH3, N2, and CF4 plasma. The band-gap of GeO2 in IL of sample can be increased with creating Ge4+ content by using NH3 plasma and MWA. A nitridation on GeOx interface layer were performed to form polar compounds GeON for sample with NH3 plasma treatment. Then the GeON polar compounds, may be efficiently annealed by MWA without additional thermal cycles which can suppress Ge out diffusion or GeO desorption that cause in high JG or remote phonon scattering. A high peak hole mobility of ~588 cm2/V-sec and very low JG of 1.88 x 10-5 A/cm2 in Ge MOSFET are simultaneously achieved by using NH3 plasma treatment at high-k/GeOx interface together with MWA.

摘要 I
目錄 V
第一章 序論 1
1.1 前言 1
1.2 使用純鍺基板作為載子通道材料 1
1.3 高介電係數(High-K)介電材料導入的原因 2
1.4 高介電係數(High-K)材料的選擇 3
1.5 介面層的形成方式 4
1.6 界面缺陷鈍化 5
1.7 氫氣電漿處理的機制與影響 7
1.8 氮氣電漿處理的機制與影響 7
1.9 微波退火的機制 8
1.10 論文架構 8
第二章 元件製程與量測 16
2.1 HfON介電層的純鍺基板P-MOSFETs元件製程流程 16
2.2 電性量測 18
2.3 物性分析 20
第三章 鍺金氧半電晶體介電層水電漿成長溫度之影響研究 23
3.1 研究動機 23
3.2 製程與量測 24
3.3 實驗結果與討論 26
3.4 結論 29
第四章 氫氣電漿處理鍺金氧半電晶體介電層搭配微波退火影響研究 40
4.1 研究動機 40
4.2 製程與量測 41
4.3 實驗結果與討論 43
4.4 結論 46
第五章 氨氣/氮氣/氟氣電漿處理介電層搭配微波退火對鍺金氧半電晶體介電層影響研究 59
5.1 研究動機 60
5.2 製程與量測 60
5.3 實驗結果與討論 62
5.4 結論 67
第六章 結論與展望 86
6.1 結論 86
6.2 未來展望 88

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