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"[ABSTRAKPemanfaatan panas yang tidak terpakai adalah salah satu bentuk efisiensi energi.Panas yang tidak terpakai dari industri dan transportasi dapat dikonversikanmenjadi energi listrik dengan menggunakan material termoelektrik. KeramikCa3Co2O6 dan CaMnO3 adalah salah satu contoh material. Penelitian yangdilakukan adalah percobaan sintesis keramik Ca3Co2O6 dan CaMnO3menggunakan metode proses reaksi padatan.Sintesis material menggunakan bahan baku berbasis karbonat, yaitu CaCO3,CoCO3 dan MnCO3. Sintesis dilakukan dengan mengacu pada diagram fasasistem Ca-Co-O dan Ca-Mn-O. Berdasarkan analisis termal, untuk mendapatkanfasa CaO, Co3O4 dan Mn2O3 maka bahan baku yang berbasis karbonat harusdikalsinasi pada suhu ≥ 800°C. Suhu pembentukan Ca3Co2O6 berdasarkandiagram fasa sistem Ca-Co-O dan Ca-Mn-O adalah pada rentang suhu 824-1027°C dan CaMnO3 pada rentang suhu 1100-1600°C dengan lingkunganatmosfir udara bebas.Hasil sintesis diperoleh fasa Ca3Co2O6 terbentuk paling baik pada suhu 1000°C,tetapi masih terdapat fasa lain yaitu CoO dan Co3O4. Fraksi berat masing-masingfasa adalah Ca3Co2O6 : CoO : Co3O4 = 71,1 : 21,6 : 7,3. Sedangkan pada sintesisCaMnO3, fasa CaMnO3 sudah terbentuk satu fasa pada suhu 1100°C.

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ABSTRACTHeat is one kind of energy source that can increases energy efficiency. Heat fromindustrial and transportation can be converted into electrical energy through athermoelectric material. Ca3Co2O6 and CaMnO3 ceramics are thermoelectricmaterials. The main idea of this research is synthesis of Ca3Co2O6 and CaMnO3ceramics using solid state reaction method.Synthesis of thermoelectric materials using carbonate-based raw materials. Theraw materials are CaCO3, CoCO3 and MnCO3. Synthesis of material is done withreference to the phase diagram system of Ca-Co-O and Ca-Mn-O. Based onthermal analysis, the carbonate-based raw materials must be calcined attemperature ≥ 800°C to get CaO, Co3O4 and Mn2O3 phases. The temperatureformation of Ca3Co2O6 and CaMnO3 are about 824-1027°C based on phasediagram system of Ca-Co-O and 1100-1600°C based on phase diagram system ofCa-Mn-O in air.Ca3Co2O6 phase is formed at temperatures of 1000°C, but there were some otherphase, i.e,. CoO and Co3O4. Weight fraction of each phase is Ca3Co2O6 : CoO :Co3O4 = 71,1 : 21,6 : 7,3. While CaMnO3 one phase is already formed at 1100°C.;Heat is one kind of energy source that can increases energy efficiency. Heat fromindustrial and transportation can be converted into electrical energy through athermoelectric material. Ca3Co2O6 and CaMnO3 ceramics are thermoelectricmaterials. The main idea of this research is synthesis of Ca3Co2O6 and CaMnO3ceramics using solid state reaction method.Synthesis of thermoelectric materials using carbonate-based raw materials. Theraw materials are CaCO3, CoCO3 and MnCO3. Synthesis of material is done withreference to the phase diagram system of Ca-Co-O and Ca-Mn-O. Based onthermal analysis, the carbonate-based raw materials must be calcined attemperature ≥ 800°C to get CaO, Co3O4 and Mn2O3 phases. The temperatureformation of Ca3Co2O6 and CaMnO3 are about 824-1027°C based on phasediagram system of Ca-Co-O and 1100-1600°C based on phase diagram system ofCa-Mn-O in air.Ca3Co2O6 phase is formed at temperatures of 1000°C, but there were some otherphase, i.e,. CoO and Co3O4. Weight fraction of each phase is Ca3Co2O6 : CoO :Co3O4 = 71,1 : 21,6 : 7,3. While CaMnO3 one phase is already formed at 1100°C., Heat is one kind of energy source that can increases energy efficiency. Heat fromindustrial and transportation can be converted into electrical energy through athermoelectric material. Ca3Co2O6 and CaMnO3 ceramics are thermoelectricmaterials. The main idea of this research is synthesis of Ca3Co2O6 and CaMnO3ceramics using solid state reaction method.Synthesis of thermoelectric materials using carbonate-based raw materials. Theraw materials are CaCO3, CoCO3 and MnCO3. Synthesis of material is done withreference to the phase diagram system of Ca-Co-O and Ca-Mn-O. Based onthermal analysis, the carbonate-based raw materials must be calcined attemperature ≥ 800°C to get CaO, Co3O4 and Mn2O3 phases. The temperatureformation of Ca3Co2O6 and CaMnO3 are about 824-1027°C based on phasediagram system of Ca-Co-O and 1100-1600°C based on phase diagram system ofCa-Mn-O in air.Ca3Co2O6 phase is formed at temperatures of 1000°C, but there were some otherphase, i.e,. CoO and Co3O4. Weight fraction of each phase is Ca3Co2O6 : CoO :Co3O4 = 71,1 : 21,6 : 7,3. While CaMnO3 one phase is already formed at 1100°C.]"

"Pada artikel ini dibahas mengenai pengaruh Mole fraction (x) dan Profil germanium pada basis SiGe HBT terhadap unjuk kerja Frekuensi dan Noise Figure (Fn) devais. Model parameter HBT SiGe ditentukan AE0,25  10  m2, WE10 nm, WB 40 nm, WC 350 nm, NE1021cm-3, dan NB 10 19 cm-3.Dari hasil analisa dapat disimpulkan bahwa profil Ge segiempat dengan mole fraction (x) 0.05 menghasilkan current gain dc (βdc), fT dan fmaks terbesar yaitu 149, 109 GHz dan 116 GHz dibanding profil trapesium yang bernilai 140, 103 GHz dan 109 dan segitiga bernilai 136, 103 GHz dan 109 GHz. Ketika mole fraction (x) dinaikkan menjadi dua (2) kali current gain dc (βdc),fTdan fmaks untuk profil segiempat naik masing-masing 39%, 4% dan 3% sedangkan untuk trapesium menjadi 39%, 4% dan 0%. Profil Ge segiempat mempunyai nilai Noise Figure (Fn) terendah yaitu 0.0964 dB, dibandingkan profil trapesium dan segitiga yaitu 0.108561 dB dan 0.1278 dB, ketika mole fraction (x) dinaikkan dua kali, maka Fn akan naik sebesar 45 % untuk profil segiempat dan 16% untuk profil trapesium.

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This paper investigates effect of fraction mole (x) and germanium profile on the Frequency Response and Noise Figure Performance (Fn) of SiGe HBTs. The model are quantified from HBT SiGe IBM model first generation with an parameter AE0,25 10m2WE10 nm, WB40 nm, WC350 nm, NE1021cm-3, dan NB1019cm - 3.We conclude that a SiGe HBT with fraction mole (x) 0.05 and profile Germanium is square deliver the current gain dc (βdc), fT dan fmaks are optimal i.e 149, 109 GHz dan 116 GHz just than the profile Trapezoid i.e 136, 103 GHz dan 109 GHz. When fraction mole (x) is raised twice, the current gain dc (βdc), fTdan fmaks increased 39%, 4% dan 3% for the square profile whereas the trapezoid profile increased 39%, 4% dan 0%. The Square profile of Germanium is optimum for Noise Figure (Fn) i.e 0.0964 dB lower than the profile of germanium trapezoid and triangle given the value 0.108561 dB and 0.12 78 dB."

"Jika dua bahan semikonduktor yang tidak sama digabungkan, sambungannya disebut heterojunction. Karena kedua bahan semikonduktor tersebut mempunyai bandgap yang berbeda, akan terjadi diskontinuitas energi pada persambungannya. Sambungan yang terbentuk dapat berupa sambungan abrupt atau graded. Sambungan abrupt terjadi jika perubahan dari satu bahan ke bahan lainnya terjadi secara tiba-tiba, sedangkan sambungan graded terjadi jika perubahan dari bahan satu ke bahan lainnya terjadi secara perlahan-lahan. Pada penelitian ini dibuat rancangan HBT (Heterojunction Bipolar Transistor) Si/SiGe sambungan abrupt yang dapat memberikan frekuensi transit (fT) dan penguatan arus yang optimum. Untuk memperoleh frekuensi transit tersebut digunakan model struktur divais dengan NE=I01 S cm-3, NB=5.1019cm"3, dan WE=-50 nm. Lebar basis W8 dibuat bervariasi antara 10 - 50 nm dengan kenaikan 10 nm dan fraksi mol Ge dibuat bervariasi antara 0.15 sarnpai 0.25 dengan kenaikan 0.025. Dalam perancangan digunakan model HBT yang memasukkan mekanisme drift, difusi dan emisi termionik. Model tersebut juga digunakan untuk menentukan densitas arus basis, arus kolektor dan penguatan arus untuk lebar basis dan fraksi mol Ge yang bervariasi. Hasil perhitungan menunjukkan bahwa pada HBT yang diteliti komponen arus emisi termionik sekitar 2.8 sampai 4.2 kali lebih besar dibanding dengan anus drift-difusi. Pengurangan lebar basis dari 50 nm menjadi 10 nm pada HBT dengan N E.--1018 cm-3, NB=5.109 cm 3, WE=50 nm, dan x .25 dapat meninakatkan frekuensi transit dari 52 GHz menjadi 178 GHz, sedangkan besarnya penguatan arus untuk WB=1O nm adalah 312 kali.

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When two different semiconductor materials are used to form a junction, the junction is called a heterojunction. Since the two materials used to form a heterojunction will have different bandgaps, the energy band will have a discontinuity at the junction interface. The type of the junction could be an abrupt or graded junction. In abrupt junction, the semiconductor changes abruptly from one material to the other material. on the other.hand in graded junction, the composition of materials are graded.

In this work, we designed abrupt junction Si/SiGe HBT (Heterojunction Bipolar Transistor) with optimum transit frequency VT) and current gain. To achieve that transit frquency, the divals structure model with NE=1418 cm 3, Na 5.1019cm 3, and WE-50 nm is used. Base width WS was changed between 10 - 50 run with 10 nm increment and the Ge mole fraksi was between 0.15 - 0,25 with 0.025 increment. The model of HBT which include the drift, difussion and thermionic emission is used. The HBT model is also used to calculate the base and collector current density and the current gain for variable base width and Ge mole fraction.

The result show that the thermionic emission current is 2.8 until 4.2 times higher than the drift-difussion current. If base width is decreased from 50 nm to 10 nm of an HBT with NE=1018 cm-3, N8=5.1019 cm-3, WE=50 nm, and x=0.25 , the transit frequency is increased from 52 GHz to 178 GHz. The current gain for WB= 10 nm is 312 times larger."