Deep Trench Capacitors (DTC) is a dead end – CNF-MIM is the way forward

Think about the smart­phone in your pock­et. It’s a mar­vel of engin­eer­ing, packed with incred­ible com­put­ing power, all thanks to a myri­ad of tiny com­pon­ents. Among these unsung her­oes are capa­cit­ors, which store and release elec­tric­al energy to keep everything run­ning smoothly. But the industry is nev­er sat­is­fied, always want­ing more capa­cit­ance in less space. This has led to a race to find new capa­cit­or tech­no­lo­gies. For a while, the deep trench capa­cit­or (DTC) tech­no­logy looked prom­ising. But now they are approach­ing the lim­its of what phys­ics will allow, and the industry is still not sat­is­fied. For­tu­nately, a new con­tender has emerged: car­bon nan­ofiber met­al-insu­lat­or-met­al (CNF-MIM) capa­cit­ors. CNF-MIM capa­cit­ors don’t have the inher­ent lim­it­a­tions of DTC, but instead point the way for­ward to even more capa­cit­ance in even less volume.

Subtractive vs. additive: two ways of creating

To under­stand why DTC tech­no­logy faces inher­ent lim­it­a­tions while CNF-MIM rep­res­ents the future, let’s pic­ture two dis­tinct ways of cre­at­ing. DTC is like carving a sculp­ture from a block of marble – it’s a sub­tract­ive pro­cess. You start with the mater­i­al and remove what you don’t need. In con­trast, CNF-MIM is like sculpt­ing with clay – an addit­ive pro­cess. Here, you build up a struc­ture lay­er by lay­er, adding mater­i­al pre­cisely where needed.

The DTC jour­ney starts with a sil­ic­on wafer. From that sur­face, pre­cise pro­cesses cre­ate deep trenches, like mini­ature wells in the ground. These trenches are then care­fully filled with dif­fer­ent mater­i­als to form a capa­cit­or. While this approach has pushed the bound­ar­ies of what’s pos­sible, it’s run­ning into phys­ic­al bar­ri­ers. It’s like a sculptor try­ing to carve an impossibly intric­ate design from an ever-smal­ler block of marble.

The physical limits of DTC

The crux of the prob­lem with DTC lies in the phys­ics of its creation.

To increase capa­cit­ance dens­ity, that cru­cial meas­ure of how much elec­tric­al charge can be stored in a giv­en space, man­u­fac­tur­ers aim to cre­ate deep­er, nar­row­er, and more numer­ous trenches. Capa­cit­ance is dir­ectly pro­por­tion­al to the sur­face area, so deep­er trenches cre­ate more wall area, increas­ing capa­cit­ance. More trenches increase the over­all area. Addi­tion­ally, capa­cit­ance is inversely pro­por­tion­al to the dis­tance between the walls. There­fore, nar­row­er trenches bring the walls closer, increas­ing capacitance.

How­ever, there’s a prac­tic­al lim­it to how deep and nar­row these trenches can be. Uni­form coat­ing of mater­i­als becomes harder and the risk of short cir­cuits or unac­cept­able leak­age cur­rent increases.

As these trenches reach their phys­ic­al lim­its, the abil­ity to improve DTC per­form­ance rap­idly decreases. Returns dimin­ish with each attempt to make the trenches more aggress­ive. Ima­gine try­ing to paint the inside of a straw with a brush, and at the same time mak­ing that straw thin­ner and longer. It quickly becomes impossible. Also, the struc­ture becomes more fra­gile with deep­er and more numer­ous trenches.

CNF-MIM: Building the future, layer by layer

Now let’s look at the Smol­tek CNF-MIM pro­cess. It is a rad­ic­al depar­ture from the sub­tract­ive meth­ods used in tech­niques such as DTC.

Instead of dig­ging trenches, CNF-MIM is man­u­fac­tured by put­ting incred­ibly thin car­bon nan­ofibers ver­tic­ally on the sub­strate. Think of it as a forest of micro­scop­ic trees. These fibers, which are 10,000 to 15,000 times thin­ner than a human hair, are metic­u­lously coated, each with a thin lay­er of met­al, fol­lowed by a thin lay­er of insu­lat­ing mater­i­al, and then anoth­er lay­er of met­al. This cre­ates a met­al-insu­lat­or-met­al capa­cit­or at the nano­scale. These lay­ers can also be repeated for mul­tilay­er capa­cit­or structures.

By mak­ing the nan­ofibers long, a large sur­face area is obtained with­in a small foot­print. By cre­at­ing a dense forest of fibers, this area is mul­ti­plied many times over. In this way, very high capa­cit­ance can be achieved without increas­ing the volume.

A transformative advantage

The advant­age is trans­form­at­ive. Where DTCs struggle with depth and width ratios in their trenches, CNF-MIM effort­lessly achieves much high­er aspect ratios because its struc­tures are added rather than sub­trac­ted. It’s like the dif­fer­ence between dig­ging a ditch and build­ing a sky­scraper. This found­a­tion­al dif­fer­ence means CNF-MIM capa­cit­ors can poten­tially achieve a vastly great­er capa­cit­ance dens­ity than is phys­ic­ally pos­sible with DTC technology.

The future of capacitors is here

As we look to the future of elec­tron­ics, the lim­it­a­tions of DTC tech­no­logy become increas­ingly appar­ent. The industry needs a solu­tion that can scale bey­ond cur­rent phys­ic­al con­straints. CNF-MIM tech­no­logy provides just that. Its addit­ive man­u­fac­tur­ing approach unlocks pos­sib­il­it­ies that are simply unat­tain­able with sub­tract­ive methods.

The poten­tial of CNF-MIM tech­no­logy was high­lighted in an inter­view with Dr. Philip Less­ner. His assess­ment acknow­ledged the ground­break­ing cap­ab­il­it­ies of Smol­tek’s CNF-MIM capa­cit­ors. This expert val­id­a­tion under­scores the industry’s grow­ing interest in addit­ive man­u­fac­tur­ing and the revolu­tion­ary poten­tial of CNF-MIM technology.

A clear path forward for Smoltek

For Smol­tek share­hold­ers and investors, the implic­a­tions of this shift are clear. DTC tech­no­logy, while an impress­ive feat of engin­eer­ing, rep­res­ents a dead end in capa­cit­or devel­op­ment. The future belongs to innov­at­ive solu­tions like CNF-MIM that tran­scend cur­rent phys­ic­al limitations.

As the elec­tron­ics industry con­tin­ues its relent­less pur­suit of mini­atur­iz­a­tion and enhanced per­form­ance, the demand for high­er-per­form­ing capa­cit­ors will only intensi­fy. CNF-MIM tech­no­logy not only meets these cur­rent chal­lenges but also provides a clear path­way for future advance­ments. It’s not just a tem­por­ary solu­tion but a long-term answer to one of the most press­ing chal­lenges facing the elec­tron­ics industry.

CNF-MIM isn’t just about bet­ter capa­cit­ors; it’s about the future of elec­tron­ics. As a Smol­tek investor, you’re a part of build­ing it.